Introduction: Abolitionism and the Unity of All Humans

Before and outside abolitionism, slavery is not a crime, but a legal institution justified by ideologies that present certain groups as so flawed that their enslavement is culturally and morally acceptable. These ideologies rely on othering rationales, such as Aristotle’s theory of the natural slave, which deny the “enslavable other” the protection and benefits of belonging in society. To understand the development of global abolitionism, one has to understand how othering rationales that supported the enslavement of particular groups were progressively refuted.

Slavery was always morally problematic, but outside abolitionism moral concerns focused on the question of who should, or shouldn't, be legitimately enslaved and how those enslaved ought to be treated. Othering provided the most effective psychological mechanism to distinguish between the non-enslavable Self and the enslavable Other. Those deemed enslavable were turned into classificatory outsiders, unprotected by ties of kinship, loyalty, and reciprocity. The majority of those falling into this category were portrayed by their enslavers as religious outcasts and exotic foreigners, sometimes subhuman.¹ But they could also be outsiders within: sinners, prisoners, fallen people judicially stripped of the rights protecting other members of society from enslavement. Thus, pro-slavery ideologies rely on theories of fundamental difference that justify slaving by inventing categories of enslavable others, who carry within them the seed of their exceptional exploitability. These theories also exonerate slavers from the charge of cruelty and inhumanity, as they allow them to imagine themselves as merely accommodating the order of nature or the will of God.

When all humans are recognized basic rights and prerogatives, the rationale for slavery crumbles. The best example of the interconnection between universalism and anti-slavery is the United Nations’ Universal Declaration of Human Rights (UDHR) of 1948, which prohibits slavery and servitude “in all their forms” in its article 4.² It is not by chance that opposition to slavery occupies such a central place in an organization whose very existence is predicated on the idea of global ecumene and universal human rights. The logics of exclusion that support slavery cannot operate under these ideological premises. The UDHR exemplifies modern abolitionism. Its objectives differ from those of ancient reformers and ameliorationists who criticized mis-targeted slaving and recommended the humane treatment of slaves. Modern abolitionism asserts that no person should be in a relation to another that is analogous to the relation between the owner and the thing owned. The overwhelming powers that property law attributes to owners cannot be held toward other humans.³

Abolitionism involves political action aimed at enrolling governments and citizens in the suppression of slavery and the slave trade. It happens when people, as a result of their own experiences or their reflections on the experiences of others, come to see slavery as unjust and mobilize to bring about its end. When their movements are successful, slavery becomes a crime, slaveholders criminals, and the suppression of slavery an obligation for national and international governing bodies. Abolitionism does not have a single origin; it developed independently in different places and societies through the actions of persons confronted with different forms of slavery. But one particular strand of abolitionism, developed around Atlantic slavery’s deadly coupling of capitalism and racism, started acquiring global momentum at the height of the transatlantic slave trade. Abolitionist movements in sites connected to Atlantic slavery were brought together by common objectives and by the appeal of increased impact resulting from collaboration.⁴ This strand of abolitionism progressively enrolled supporters and collaborators all over the world. It became genuinely global and rendered paradigmatic what had hitherto been only one particular historical form of slavery, the one connected to the transatlantic slave trade, with its peculiar emphasis on providing a disposable male labor force to maximize the profits of global capitalism.⁵

As the horrors of Atlantic slavery became widely known, abolition imposed itself against the economic interests of businesses that thrived through slave labor. The anti-slavery views of a broad range of groups coalesced. Enslaved persons, freed slaves, pious believers, lay humanitarians, revolutionaries and those fighting in their armies, humanist scientists, liberal politicians, and compassionate publics in different corners of the world used different strategies to achieve anti-slavery’s victory over pro-slavery. Ideologies that justified othering, hierarchy, and slavery had different genealogies in different world regions. Hence, localized anti-slavery followed different intellectual and political trajectories.⁶ Different abolitionist groups and individuals—some issued from slavery, others from privileged elites—mobilized against slavery and the slave trade. In this process, the testimonies of those who had experienced enslavement played a unique role in giving abolitionist movements the irrefutable evidence and moral impetus they required to turn public opinion in support of abolition. But, with the exception of successful revolutions (such as in France and Haiti), the abolitionist approaches that shaped state politics tended to be those least harmful to the interests of the powerful. The professionals who controlled the law belonged to the upper classes.⁷ Slave owners’ compensation, long-term apprenticeships, and vagrancy laws are but a few examples of how conservative interests influenced the application of abolitionist principles.

"Abolitionism" is a generic term. It must be historicised and understood as a process that involved different positions and approaches that changed in time. For the purpose of broad historical reconstruction, it may be helpful to distinguish three main stages in global abolitionism, none of which was either static or internally homogenous. In the first stage (c. 1670–1800), abolitionists were minority groups who questioned the moral legitimacy of slavery and sought to bring about its de-legalization. They tried to convince as many people as possible, starting from their own constituencies, that no one deserved to be enslaved and that everyone had to be seen as a fellow human. A second period in the history of abolitionism (c. 1800–1920) began when Europe’s main empires made the abolition of the slave trade their official political stance. The Vienna Congress in 1814–1815 marked a legal turning point with the prohibition of the slave trade ratified by Austria, France, Great Britain, Prussia, Portugal, Spain, Sweden, and Russia. Between the 1830s and 1880s, Europe’s empires integrated imperialism and abolitionism. They moved away from the egalitarian ethics of the earliest abolitionist movements and developed approaches that upheld the superiority of Europe and turned abolitionism into a legitimating criterion for interventionism and imperialism.⁸ In the last decades of the 19th century, the representatives of European empires relied upon these abolitionist rationales to justify the occupation of Africa.

A third stage in global abolitionism (c. 1920–2020) started with the creation of the League of Nations. This multilateral organization was separate from the individual empires that had heretofore set their own standards of legitimacy in dialogue with the religious authorities recognized by their suzerains. When the work of legitimation was carried out by religious leaders, suzerains in disagreement with the popes of Rome or the legal-religious authorities of Islam could, at their own risk, challenge the latter’s legitimacy and declare allegiance to other moral authorities, leading to schisms and struggles over who ought to be seen as the divinely chosen arbiter of human morality. The League of Nations followed a different approach to the setting of universalizing moral standards based on consensus, representation, and multilateralism.⁹ The League and, later, the United Nations were resented by some religious authorities as threats to their pastoral and spiritual role and by some national rulers as interferences in their sovereignty. And yet, after the end of World War II, the United Nations provided the frame of reference for anti-slavery movements worldwide.

Global abolitionist movements did not eradicate slavery but largely succeeded in delegitimizing it morally and delegalizing it in all world regions. In spite of its illegality, slavery continues to exist de facto. Furthermore, pro-slavery logics can always arise anywhere and reinstate slavery de jure. When this happens, particular groups are stereotyped, dehumanized, subjected to total control, and denied basic rights afforded to all other members of society. Soviet gulags and Nazi concentration camps in Europe in the 1930s are a case in point.¹⁰ In Euro-America, there are exceptions to the legal prohibition of slavery, the best known of which is the Thirteenth Amendment to the US constitution, which states that “Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.”¹¹ And some sections of Asian and African societies continue to support pro-slavery ideologies in specific circumstances.¹² Finally, although slavery has been delegalized worldwide, this is different from it being criminalized. Almost half of all countries in the world have not criminalized slavery; enslavers cannot be prosecuted and punished in their criminal courts.¹³ This includes, for example, South Africa, the United States, Spain, and Switzerland.¹⁴ Abolitionism has yet to fully attain its goals.

Anti-Slavery at the Dawn of Abolitionism

Critiques of slavery aimed at reform and amelioration are not rare historically. But objections to how slavery was practiced—for example, arguments against the excessive cruelty and intemperance of masters or the wrongful enslavement of groups considered non-enslavable—did not result in calls for the abolition of the institution of slavery. Yet, they contained the abolitionist rationale in embryonic form and at work on a scale smaller than the whole of humanity. They aimed to demonstrate that certain groups did not deserve enslavement and were equal in dignity to those who (wrongly) enslaved them. The principle of equality is already present in these logics, but it is not applied to humanity as a whole; it is applied selectively to particular groups and regions. Thus, in the late medieval and early modern period geographic criteria for legitimate enslavement yielded mental maps that divided the world between religiously defined enslavable and non-enslavable groups—or, in Jeffrey Fynn-Paul’s formulation, between slaving and no-slaving zones.¹⁵ Hannah Barker has shown that Christian and Muslim societies around the Mediterranean and Black Sea enslaved each other but shared a common culture of slavery: their criteria and conventions for regulating slavery and the slave trade mirrored one another.¹⁶

The concern to avoid enslaving co-religionists was not rooted in the abolitionist principle that slavery is an aberration but in the perceived spiritual perils of mis-targeted enslavement. The best-known early Christian arguments for selective abolitionism are those of Iberian scholars. The Dominican Bartolomé de Las Casas, famous advocate for the demise of Amerindian slavery, in 1518 proposed to the Spanish Crown that it replace Indian laborers with Africans. He later repented for his suggestion; in his Historia de las Indias and in his Brevísima relación de la destrucción de África (1552), he denounced African slavery.¹⁷ It is probable that Muslim authors like al-Balbali, active in the 1530s and one of Ahmad Baba’s sources, were aware of these Iberian debates, which they would have interpreted according to their own realities and concerns about the religious prohibition to wrongfully enslave other (black) Muslims.

Concurrently, in Europe it was not uncommon for attackers of Indian slavery to defend African enslavement. Bartolomé de Albornoz, Spanish jurist of the Salamanca school and professor of law at the University of Mexico, condemned not only the slave trade but also slavery itself, including the enslavement of Africans, in his Arte de los contractos (1573). He did not call for the emancipation of enslaved persons, but his denunciation of the institution was sufficiently radical for his book to be placed under the index of the Inquisition.¹⁸ Yet, his voice remained isolated until the late 17th century. Not Albornoz, but thinkers like Alberico Gentili, Francisco de Vitoria, and Hugo de Groot (Grotius) provided arguments more in tune with the moral and political rationales of European empires in the late 16th and early 17th centuries.¹⁹

In 1615, the Sanhaja scholar Ahmad Baba returned to his hometown of Timbuktu after over twenty years of exile in Marrakesh in the Sultanate of Morocco. Shortly after his return, he wrote the famous treatise Miʿrāj al-ṣuʿūd ilā nayl ḥukm mujallab al-Sūd (The Ladder of Ascent towards Grasping the Law Concerning Imported Blacks).²⁰ The “imported blacks” mentioned here referred to the black West Africans who were being traded as slaves across the Sahara into North Africa. Ahmad Baba wrote in reply to the questions of Sa’id ibn Ibrahim al-Jirari, probably a merchant, from the northern Saharan oasis of Tuwat. Tim Cleaveland argued that while in exile in Marrakesh, Ahmad Baba was confronted with racial arguments for the enslavement of black Sudanese, which he became determined to refute.²¹ As a merchant, Al Jirari would have regularly encountered sub-Saharan “black” captives who claimed to be Muslim; he consulted the renowned scholar on how to deal with such cases. Ahmad Baba stated that the peoples mentioned by al-Jirari had never been conquered but had embraced Islam of their own free will and therefore could not be legitimately enslaved by fellow Muslims. Black Muslims had to be treated just like all other Muslims regarding enslavability.²²

Racism intensified in the Atlantic space in the course of the 17th century.²³ In the 1660s, the Dominican Jean-Baptiste du Tertre, who had worked as a missionary in the French Caribbean, idealized the purity of the Indian savage but represented black Africans as “natural slaves.”²⁴ Arguments such as his, promulgated by respected members of their communities, systematically dehumanized African slaves in the Atlantic, the Caribbean, and the Americas. Certain religious orders, such as the Capuchins and Franciscans, did denounce the extreme cruelty of Atlantic slavery. So did some representatives of African societies exposed to the brutality of the Atlantic slave trade at its point of departure.

Lourenço da Silva de Mendonça, who descended from the royal family of Ndongo of Kongo in modern-day Angola, brought to the Vatican a law case against Atlantic slavery in the early 1680s. José Lingna Nafafé has shown that Mendonça formed an alliance with a pan-Atlantic network of activists who developed a universalist argument against the enslavement not just of Africans, but also of Indigenous Americans, Brazilians, New Christians, and Portuguese members of the “Hebrew Nation”.²⁵ Collective, organised resistance against Atlantic slavery is attested in research on multiple sites, from West Central Africa and the Gulf of Guinea to the metropoles of Europe's slave-trading empires, to the Americas and Brazil. Research based mainly on Portuguese and Spanish sources has documented early forms of African resistance to enslavement across the Atlantic.²⁶ Pleas against the unjust enslavement of individuals and groups were frequent at the dawn of global abolitionism. Africans and members of nations who were the victims of Euro-American slaving led these initiatives and demanded that various publics and variously constituted tribunals listen to their arguments. By denouncing the cruelties imposed against those enslaved they pioneered important multilateral antislavery initiatives. Critical editions of their texts and further research on their work will advance knowledge on their specific understandings of slavery and on the exact nature of their objections to it.

Full-fledged abolitionism dawned when no one could be portrayed as justifiably enslavable. This idea has at least two major intellectual genealogies: one is mainly secular, non-religious, and rooted in enlightenment thought. The enlightenment challenged ideologies that justified allegedly God-given hierarchies. Its ideas were at odds with pro-slavery positions and would be central to the tactics of anti-slavery movements worldwide. Yet, its original inspiration was not solely a reaction against the slave trade: its causes were broader. The second approach, quintessentially religious, developed from reformist and minoritarian religious positions. Having been stigmatized for their beliefs, racially stigmatised religious minorities, New Christians, Quakers and the members of other Protestant sects were peculiarly aware of the arbitrariness of the criteria that determined who was, and who was not, exposed to persecution. Initially, many Quakers considered it acceptable to own slaves and lent each other money to acquire them. But in the early 18th century, rising numbers of Quakers empathized with the enslaved and played a major role in the initial transformation of abolitionism into a global movement.

Abolitionism in North America

Evangelicalism influenced the earliest abolitionist movements in North America.²⁷ Some of the first abolitionist networks developed within German-speaking post-Reformation sects and pietist communities such as the Moravians, a Lutheran and Hussite movement that originated in the Holy Roman Empire.²⁸ Between the late 17th and the mid-18th centuries, these movements preached egalitarianism. To be sure, this was not egalitarianism in the modern sense of the term. Inequalities of gender, race, and status were broadly accepted at the time. But Evangelicals rejected radical racist theories that saw blacks as enslavable because they were allegedly altogether different from whites. They instead emphasized common humanity with slaves: in particular, they argued that the body of slaves contained an immortal soul like that of their tormentors. This specific point was not a claim that all people were equal, but it was egalitarian in its assertion that Blacks and Whites, slaves and free, were all equal in the eyes of God. Puritan Richard Baxter reminded his readers in A Christian Directory: Now, a Summ of Practical Theology, and Causes of Conscience (1673) that the souls of slaves were “just as capable of salvation as yours.”²⁹ In 1688, during a meeting of Friends (Quakers) in Germantown, Pennsylvania, Francis Daniell Pastorius, Gerret Hendericks, Derick up de Graeff, and Abraham up den Graef presented a petition to end the practice of slavery in their community.³⁰ The petition called on all Quakers, outraged by the captures of Christians by Muslim Turks, to extend the same empathy to Africans. Germantown’s petition supported an ethics of reciprocity and evoked the Golden Rule: Don’t do to others what you wouldn’t want to be done to you. Puritan Judge Samuel Sewall’s pamphlet The Selling of Joseph: A Memorial published in Boston in 1700 is another example of early North American attempts to condemn slavery as morally repugnant.³¹ Sewall’s pamphlet resembled the Quakers’ petition in the plainness of its style, which contrasted with the opulent Catholic and Anglican rhetoric.³² These were the early steps of a strand of abolitionism that would take center stage on a global scale.

Quakers on both sides of the Atlantic played a prominent role. In his Historical Account of Guinea published in 1762, Anthony Benezet, a Quaker of Philadelphia, affirmed the equality of Africans and Europeans, provided empirical data on the size and organization of the transatlantic trade, and reproduced eyewitness accounts of the plight of slaves.³³ By the time Benezet’s book came out, it resonated with the anti-slavery views of many different groups that had started mobilizing against slavery in their communities. In the 18th century, free blacks and (ex-)slaves developed their own religious and ideological objections against slavery. Black abolitionists, most of whom had experienced enslavement directly or descended from slave parents, played a major role in Euro-American abolition movements.³⁴ They operated both in collaboration with white Euro-American abolitionist movements and through separate movements that mostly chose to include the words African or black in their denominations. For example, the Free African Union Society, whose leading members included mostly free blacks such as Prince Amy, Abraham Casey, Newport Gardner, Cesar Lyndon, Salmar Nubia, Anthony Taylor, and Bristol Yamma, was founded in Newport (Rhode Island) in 1780. Some of its members were in favor of returning to Africa. Nubia traveled to Liberia in his old age, together with Gardner, but died shortly after their arrival.³⁵ Connections between enslaved blacks and free persons of slave descent reinforced transatlantic continuities in abolitionist thought and action.

Like the post-Reformation sects, many early black abolitionist movements took shape in opposition to mainstream white-led religious groups that discriminated against them. Absalom Jones and Richard Allen founded, respectively, the African Episcopal Church and the Methodist Mother Bethel Church of Philadelphia after leading a walkout at St. George’s Methodist Church in 1792. They had been forced to stop praying, move out of the front benches reserved for whites, and go to the segregated space reserved for blacks. The Reverend Thomas Paul, a Baptist minister from New Hampshire, led a similar walkout in Boston in 1805, and then founded the African Baptist Church.³⁶ Black community organizations enabled the spread of abolitionist ideas and the development of a black abolitionist political consciousness that led to the founding of new churches, schools, and benevolent societies that emphasized African identity. Black Free Masons started establishing separate lodges in the 1770s. Black American lodges carried some resemblances with West African secret societies and advocated for equality and universal brotherhood. Prince Hall, pioneer of African American Free Mason lodges in Boston and North America, promoted an ethics of universal love to all humankind.³⁷

Those with firsthand experience of slavery played a major role in countering pro-slavery arguments across continents and oceans, either directly through their speeches and autobiographic texts or as authorities cited by other abolitionists. From the poetry of Phillis Wheatley to the autobiographic narratives of authors like Ottobah Cuguano and Olaudah Equiano to the relentless work to save persecuted families and individuals of activists such as Harriet Tubman to the epistles of Ignatius Sancho to forms of black associationism such as grassroots networks aimed at community uplift to the oratory of towering abolitionists like Frederick Douglass, the coordinated actions of black abolitionists undermined the defensibility of slavery. Both their own writings and reports of their actions became widely known and were quoted extensively by Atlantic abolitionists in England and North America.

The trajectory that led to abolition in the United States was far from linear. Slavery started being phased out legally after the War of Independence against Britain. The northern states opposed slavery shortly after independence, with Vermont and Pennsylvania passing gradual abolition laws in 1777 and 1780, respectively. In 1783, Massachusetts became the first state to declare slavery illegal, and by 1804, most of the northern states had done the same. But the passing of laws did not end the vulnerability of racialised and marginalised groups to enslavement, as attested by legal suits brought by people of colour including Native Americans.³⁸ Those who stood most to lose from the emancipation of enslaved persons objected vehemently to immediatism and instead supported various versions of amelioration that would allegedly improve the conditions of enslaved blacks but keep the institution legal. George Fitzhugh, an anti-abolitionist Virginian author, quoted Aristotle in defense of hierarchical slave–master relationships. He denounced the views of the philosophers Locke and Hobbes that humans were naturally free. Rather than denying the humanity of slaves, the argument put forward by Fitzhugh in Cannibals All, or Slaves without Masters (1857) was based on the idea that improved conditions of slavery were preferable to the living conditions of the English proletariat, which Fitzhugh called “slaves without masters.”³⁹

Intense ideological struggles were correlated to the rising precariousness felt by planters and slaveowners. In 1860, E. N. Eliott, president of the Mississippi Planters College, published a collection of texts designed to convince American public opinion of the justice of arguments in favor of slavery. His reasoning combined a rhetoric of improvement with racism:

That the negro is today an inferior species, or at least an inferior variety of the human race, is now well established and must, we believe, be recognized by all. . . . American slavery has already achieved the most encouraging results in the upliftment of the negro race that lives among us; they are now as superior to the natives of Africa as the whites are to them.⁴⁰

In North America, the clash between the entrenched racism of slaveholders and the resistance of the (formerly) enslaved and those committed to abolition led to a civil war. Slavery was abolished throughout the United States after the Civil War, with the passage of the Thirteenth Amendment to the United States Constitution in 1865, under President Abraham Lincoln. However, variants of pro-slavery positions continued to proliferate after 1865 abetted by resilient state-supported racism.

Abolitionism in France and the United Kingdom

The Lumières were an internally diverse phenomenon with a complex relation to slavery. The main Enlightenment thinkers questioned the hegemonic function of religion and exalted scientific reasoning as liberating. This was a fundamental difference from the anti-slavery arguments that were being developed by the Evangelicals. Furthermore, the Enlightenment is a broad caption for a plethora of diverse positions. Some of its thinkers believed in the alleged superiority of European civilization; others championed ideas of equality and universal brotherhood.⁴¹ In the first half of the 18th century, Jean-François Melon, one of the key ideologues of enlightenment political economy, declared slavery and the slave trade necessary to imperial economies.⁴² In his Esprit des Lois (1748), the Baron de Montesquieu denounced slavery, ridiculing pro-slavery claims that blacks were not humans. And yet, he did not reject entirely the economic, legal, and political rationales for slavery. In the mid-18th century, Adam Smith and John Millar, leading figures of the Scottish Enlightenment, endeavored to prove the economic superiority of free over slave labor. Similar points were made by Benjamin Franklin in his Observations Concerning the Increase of Mankind, Peopling of Countries published in Boston and London in 1755. These economic arguments were flawed but nevertheless became hugely influential in turning some sections of public opinion in favor of abolition.

In France, a fundamental work that epitomized the Lumières’ anti-slavery positions was the Histoire philosophique et politique des établissements et du commerce des Européens dans les deux Indes (better known as Histoire des deux Indes), with contributions by multiple authors, published in three editions in 1770, 1774, and 1780 and attributed to Abbot Guillaume Thomas Raynal. In his sections, Denis Diderot objected to slavery on philosophical and moral grounds. Nicolas de Caritat, Marquis of Condorcet, asserted the equality of all humans in his Réflexions sur l’esclavage des Nègres, published under a pseudonym in 1781 and stating at its start that “[t]o enslave a man, to buy him, sell him and keep him enslaved, are true crimes worse than theft.” Condorcet supported immediatism without compensation for slave owners. If such a statement was ahead of its time for a member of the French aristocracy, such views were not unheard of in Europe at the time. In a letter dated January 27, 1778, the African Englishman Ignatius Sancho, voiced reflections on the slave trade evoked in him by a book on slavery that Mr. F., the recipient of his letter, had sent to him:

Upon the unchristian and most diabolical usage of my brothers Negroes, the illegality, the horrid wickedness of the traffic, the cruel carnage and depopulation of the human species, is painted in such strong colours, that I should think would (if duly attended to) flash conviction, and produce remorse in every candid reader. . . .⁴³

These ideas were circulating broadly within Europe and across European dominions in the Atlantic. Expressed by persons of African descent they acquired a special force. Authors like Sancho and Wheatley were cited by European abolitionists such as Thomas Clarkson and abbée Gregoire.⁴⁴ S. E. Ogude has suggested that Sancho and Wheatley created the language that enabled Cugoano and Equiano to denounce slavery and contribute to the development of a new black consciousness in the late 18th century.⁴⁵ Olaudah Equiano, captured in the Ibo region of today’s Nigeria in his childhood and brought to the Caribbean, purchased his freedom in 1766 and became a major abolitionist. In 1779, his request to be ordained and sent to Africa as a missionary was turned down by the bishop of London. While certain avenues were foreclosed to him, Equiano’s descriptions of Africa as a wealthy land peopled by affable societies did much to consolidate the view that the inhumane slave trade should be replaced by legitimate trade in Africa’s raw materials. His autobiography, first published in 1789, went through nine editions in Equiano’s lifetime. Zeyad el-Nabolsy has argued that it should be seen as representative of the more radical strands of the Enlightenment and not a voice external to an allegedly “European” Enlightenment.⁴⁶ It was read and circulated broadly in abolition societies and clubs, such as the Society for Effecting the Abolition of Slave Trade, founded in 1787 in London (three years after Pennsylvania Abolition Society, founded in 1784), the Sons of Africa (founded by educated Africans, also in London, in the late 18th century), and the Société des amis des Noirs, founded in 1788 in Paris.⁴⁷

These societies were international and interconnected. Their most active members knew each other and were among the first representatives of a genuinely global civil society committed to ending chattel slavery and the slave trade. Individuals like Olaudah Equiano, Toussaint Louverture, Thomas Paine, and Francisco de Miranda participated in multiple anti-slavery and anti-colonial movements that spanned across countries and continents. Intellectually, they were influenced by multiple liberation discourses. Information circulated across Africa, Europe, the Caribbean, and the Americas not only in written form but also by word of mouth, not only among intellectuals but also among enslaved and freed persons, low-ranking military men, mariners, missionaries, religious communities, and female and male workers.⁴⁸ Some groups were peculiarly mobile. Enslaved in North America, freed in Nova Scotia, and resettled in Africa’s “Province of Freedom,” some of the earliest settlers of Sierra Leone had been exposed to multiple intellectual influences and had crafted an original society that defended its idiosyncratic positions and interests in relation to British ones.⁴⁹

In Britain, the Quakers’ experience in record keeping and accounting facilitated the emergence of abolitionist tactics based on careful documentation. Quaker friends of the abolitionist Thomas Clarkson encouraged him to study the workings of slave ships. Soon, these ships became an icon of anti-slavery propaganda across the empire. Vivid descriptions of the horrors of the enslaved’s conditions aboard of slave ships, such as the witness accounts of Alexander Falconbridge, who had practiced as a surgeon in four Atlantic voyages between 1780 and 1786, reinforced Clarkson’s propaganda.⁵⁰ Clarkson’s abolitionist strategy also owed much to Benezet’s method. Clarkson published in 1786 his essay on the Slavery and Commerce of the Human Species, Particularly the African, based on his Latin essay that had won an award at Cambridge. At the same time, Quaker writers in the United Kingdom produced an extraordinary amount of anti-slavery pamphlets and writings.

The presence of Anglicans like Granville Sharp and Thomas Clarkson lent credibility to abolitionism in Parliament, which began to seriously consider the question of abolition. Member of Parliament (MP) William Wilberforce campaigned for it. African ex-slaves continued to play a major role. Clarkson toured the United Kingdom and gave public lectures at which he displayed the contents of his famous “campaign chest” filled with African produce to convince his audiences that “legitimate trade” in African goods was not only feasible but would also turn African societies into potential consumers of Britain’s industrial products. Another economic tactic developed by British abolitionists urged consumers to boycott slave-produced West Indian sugar and rhum:

For let us not think that the crime rests alone with those that conduct the traffic, or by legislature by whom it is protected: if we purchase the commodity we participate in the crime. The slave-dealer, the slave-holder, the slave-driver, are virtually the agents of the consumer, and may be considered as employed and hired by him to procure the commodity. For, by holding out the temptation, he is the original cause, the first mover in the horrid process; and every distinction is done away by the moral maxim: “That whatever we do by another, we do ourselves.”⁵¹

In 1791, a major event in one of Europe’s richest colonies shook the world. In the wake of a series of smaller revolts in the Caribbean, connected to the preliminary stages of the French Revolution, a revolt in Saint Domingue (the French part of Hispaniola) inspired Africans enslaved in the Caribbean and worldwide. Toussaint Louverture, an educated man of slave origins, used the concepts of Liberty and Equality in his speeches to black rebels and in letters to republican “free coloreds” in attempts to win them over to his cause. The echoes of Haiti’s revolution were far-reaching. Already in November 1791, Jamaica’s British representatives communicated to the Colonial Office that “the ideas of liberty have sunk so deep in the minds of all Negroes, that wherever the greatest precaution[s] are not taken they will rise.”⁵²

On February 4, 1794 (16 Pluviôse Year II), revolutionary France abolished slavery for the first time in all its territories, legally freeing some 700,000 people “without compensating the owners for the 1000 million pounds tournaments which they represented in capital investment.”⁵³ But the historical trajectory of France’s abolition was not straightforward. Different groups appealed to ideas that supported their interests. In many colonies, slave owners were able to delay the enforcement of the new revolutionary laws.⁵⁴

Meanwhile, in Britain anti-slavery movements collected millions of signatures to petition Parliament. Some prominent MPs, skilled orators, lobbied against the slave trade first, and then slavery, among the British political establishment. Different social classes with opposing interests became involved in abolitionism. There was no single cause for their anti-slavery mobilization. British slaveowners, elites, and the working classes who signed the petitions were affected differently by abolition. Arguments that joined economic reasoning to humanitarian appeal proved particularly effective. They progressively replaced the earlier emphasis on an ethics of reciprocity with an emphasis on Europe’s superiority (often articulated in racialized terms), civilizing mission, and responsibility for domestic industrialization and trade.

After seizing power, Napoleon re-legalized slavery in 1802, showing that slavery, and the profits that some French people derived thereof, was still defensible in front of national and international publics. The Code Noir (originally developed under Louis XIV in 1685, providing detailed legislation on slavery) was reinstated. While relegalizing slavery overseas, Napoleon adopted a pragmatic stance toward slavery in Europe. He authorized the release of slaves in some of the countries he conquered. During the Italian campaign, Napoleon or his generals sometimes freed all slaves upon entering Italian cities. The Napoleon Code of 1804 outlawed slavery and provided a unified legal framework for the Kingdom of Italy until the Vienna Congress of 1814, which reorganized the political order of Europe after the fall of Napoleon.⁵⁵

In 1807 Britain abolished the slave trade. The international climate was influenced not only by the American war of independence (which Christopher Brown sees as a major influence in the development of British official abolitionism) but also by the war against Napoleon that was crucial to British status in Europe. Shortly after the 1807 abolition, representatives of the British Empire intensified diplomatic efforts to make foreign rulers sign anti-slave trade treaties. Along the Mediterranean coast of Africa, where European Christians were threatened by captivity at the hands of Muslim pirates operating in the “Barbary States,” Britain joined military muscle to diplomacy. Its operations in this region were linked to the inter-European alliances that had taken shape during its wars against France. British activities on the Atlantic coast of West Africa developed slightly later. They were carried out by a broad range of military officers, missionaries, and explorers who often had little understanding of the position of the “chiefs” whom they expected to sign treaties in exchange for a range of goods that symbolized British appreciation and vague promises of friendship. Even at the time, the legal status of these treaties was contested.⁵⁶

The Vienna Congress was both a milestone of and a turning point within global abolitionism. It marked the first inter-European commitment to “put an end to a scourge which has so long desolated Africa, degraded Europe and afflicted humanity.” But this statement also contains the key ingredients of imperial (and imperialist) abolitionism: its morally charged language is far from the ethics of reciprocity that had been central to bottom-up Euro-American abolitionism in the previous century. The logic of the Golden Rule is all but gone, replaced by unilateral saviorism. The universalist notion of “humanity” is presented as in need of protection by the major European powers who self-arrogated to themselves the mission to save Africa from “desolation” at the hand of barbaric slavers. The commitment to end slavery was ipso facto a statement of moral superiority over preceding generations of Europeans who had engaged in “degrading” slave trading and contemporary rulers elsewhere whose actions “afflicted humanity.” The main proponents of these views were, and would remain, the Atlantic powers of Europe.

It was not until 1833 that the British Empire abolished slavery everywhere in its dominions. Until the early 1830s, slave ownership in Britain was transmitted directly by inheritance and marriage settlement and indirectly by annuities and legacies, following the principles that regulated landed property.⁵⁷ When Britain abolished slavery with the Slave Emancipation Act of 1833 it took a £20 million loan to compensate British slave owners for the loss of their property. Taxpayers finished repaying this loan in 2015. Many British slave owners fought to retain rights over the enslaved and thought themselves legally and ethically entitled to do so.

Abolitionism in Catholic Europe and Latin America

Since the Middle Ages, Italy and other Catholic Southern European countries had been both importers and exporters of slaves. In the Mediterranean popular imagination, the problem of African slavery was connected to the threat of captivity faced by European Christians; it carried strong religious connotations. In the late 18th and 19th centuries, associations for the rescue and ransom of Christians in Muslim lands existed alongside small abolitionist movements led by local intellectuals and Catholic charitable institutions. In the first half of the 19th century, the capture of Europeans (and occasionally Americans) by Muslim pirates operating all along the North African coast gave rise to hostilities.

Britain, operating from Gibraltar, frequently acted as a mediator for the peaceful release of enslaved Christians from Southern European countries. When diplomatic maneuvers failed, it used its superior naval power in military operations aimed at freeing Christians and enforcing treaties that included the abolition of slavery and the rule that Christian captives be treated not as slaves but as prisoners of war. For example, in September 1816, British admiral Lord Exmouth attacked Algiers with Dutch support. His victory resulted in a Treaty of Peace that included

the abolition forever of Christian slavery; the delivery to Admiral Lord Exmouth’s flag of all the slaves in the dominions of the Dey of Algiers, to whatever Nation they may belong; to deliver also to His Lordship’s flag all the money received by the Dey for the redemption of slaves since the commencement of this year, particularly the sums paid by H.M. the King of the Two Sicilies and H.M. the King of Sardinia. . . .⁵⁸

On September 14 of that same year, a second offensive by Lord Exmouth led to the liberation of about two thousand slaves, belonging to different Christian powers.

The position of the pope in Rome had global consequences for the Catholic world. The first formal condemnation of the slave trade was contained in Gregory XVI’s apostolic letter In Supremo Apostolato of 1839, which aligned itself with the international abolitionism of the times while also referring to earlier anti-slavery actions of the Catholic Church. These positions were reiterated in Leo XIII’s encyclicals of 1888: In plurimis, on slavery’s abolition, sent to the bishops of Brazil on May 5, 1888, and Libertas, on the nature of freedom, June 20, 1888.⁵⁹ Cardinal Charles Lavigerie rose to prominence as the leading Catholic voice on abolitionism and responded directly to the pope. He criticized both the secular abolitionist logics (which he associated with the French Enlightenment), and the British emphasis on “legitimate trade,” which he denounced as too materialistic. Unlike these versions of abolitionism, Lavigerie claimed that Catholic abolitionism, of which he was the undisputed champion, focused on saving not only the bodies but also the souls of slaves. For him and those he gathered around him, abolitionism was inseparable from conversion to the Christian faith and to Catholicism specifically. In his speeches, he frequently used the metaphor of the “crusade” and portrayed Muslim slavers as primarily responsible for the practice of slavery in Africa. Key to Lavigerie’s strategy were frequent appeals to the charity of wealthy European Catholics whose donations made possible the redemption of slaves and, allegedly, the salvation of the slaves’ souls through conversion.

Italy had been importing and exporting slaves in the Mediterranean since antiquity. The Napoleonic Kingdom of Naples acquired a new penal code that abolished slavery (art. 104) as part of the French modernizing reforms introduced under Joseph Bonaparte (and then Joachim Murat) from 1806 onward. The Bourbon Kingdom of Sicily was only superficially affected by Napoleon’s rule. It abolished slavery and introduced a code inspired by the French model in 1819 following its integration into the Kingdom of the Two Sicilies (formed through the merging of the Kingdom of Naples and the Kingdom of Sicily in 1816). The area of Venice and Lombardy (Lombardo-Veneto), closely connected to Austria, abolished slavery in 1816.⁶⁰ Italian states did not have colonies abroad at this time. Therefore, unlike Great Britain, France, Spain, and Portugal, these abolitions concerned primarily slavery in the Italian Peninsula. The Grand Duchy of Tuscany had participated more actively than other peninsular rulers in international abolitionist debates. It included articles on slavery in its penal code of 1853, which appears to have been the first Italian abolitionist law that was not passed by foreign rulers. Italy’s political unification happened in 1861 (with the exception of the “Triveneto” and Lazio regions, annexed within the following decade). The first code of the post-independence unified Kingdom of Italy, the Zanardelli Code of 1889, was influenced by the latest dynamics of European abolitionism and by diplomatic exchanges with Great Britain. Italian plenipotentiary Tommaso Catalani signed an anti-slavery cooperation agreement with Robert Cecil Marquis of Salisbury on September 14, 1889.

Greece, a Christian Orthodox nation that had been subjected to Ottoman domination for almost four hundred years, freed itself from Turkish rule (Tourkokratia) at the beginning of the 1820s and abolished slavery in its independent constitution of 1823. Article 9 of the constitution stipulates that no one can be bought or sold and that whoever sets foot on Greek soil is free. Spain had interests in both the Mediterranean and the Atlantic. Unlike Greece and Italy, it was not a colonized country but a powerful colonial empire. It started reforms to slavery in its colonies in the 1810s. Concurrently, it put pressure on Britain by making its endorsement of Atlantic abolitionism conditional on British support in negotiations with North African rulers to relinquish Christian slaves and impose a stricter control on the trade of Christians in their territories. The abolition of slavery in Spanish America was intertwined with the anti-colonial struggle. Slave resistance and flights had limited the emergence of large-scale enslavement, and fugitive slaves had formed maroon communities. Many slaves and freedmen enrolled into either side of the armies fighting in South America’s anti-colonial revolutions and obtained freedom in exchange for their military support to either royalists or revolutionaries. In the Age of Revolutions, military enrollment was an important form of self-redemption by enslaved men worldwide.

Between the 1810s and the 1850s, the abolition of slavery was one of the declared goals of the anti-colonial movements in Spanish America. The anti-colonial language of freedom, independence, and equality could not but undermine pro-slavery arguments. However, not all revolutionary governments, once in power, freed slaves immediately. Gradualism, compromise, and paternalism toward Africans and Afro-descendants prevailed in the aftermath of the Spanish American independence.⁶¹ Abolition, when it happened, was followed by lingering racism in most independent Latin American nations.⁶² Concurrently, full abolition for all enslaved persons in Spain’s few remaining overseas territories only happened with the passing of the Moret Law in 1870. Slave children born after 1868 had to work for their masters as apprentices until age 22. Cuba and Puerto Rico—then Spanish colonies—rejected the ban and only abolished slavery in 1880/1886 and 1876, respectively.

Portugal abolished slavery in all its territories in 1878, but ex-slaves were subject to a long period of apprenticeship. By then, it had been over fifty years since it had lost control over its most important American colony. After Brazil’s independence in the early 1820s, Brazilian slave owners sought to retain enslaved labor in their cash crop plantations. Slavery was vital to Brazil’s economy. Abolitionists were divided between an intellectual elite, which avoided confrontations with powerful slaveowners, and more radical groups of slave descendants and freed slaves. The most rebellious of these had a fresh memory of life in Africa before captivity.⁶³ In 1845 Britain passed the Aberdeen Act, which allowed the Royal Navy to unilaterally seize Brazilian ships suspected of carrying slaves. Brazil was outraged but gave in to British pressures and abolished the slave trade in 1850.⁶⁴ Anti-Slavery International (then called the British and Foreign Anti-Slavery Society) reproached Britain for bullying Brazil. Brazilian slavery was hotly debated at the 1869 Paris Anti-slavery Conference, one of the first international conferences driven by nongovernmental abolitionists. Two years later, a large slave revolt broke out. International powers condemned the rebels, and even the Antislavery Reporter supported Brazilian repression arguing that “Brazil needs internal peace to flourish.”⁶⁵ Brazil’s final 1888 abolition, known as the Lei Áurea, the Golden Law, passed by Brazil’s ultra-Catholic regent princess Isabel, was one of the latest in the Atlantic space. It resulted from a combination of factors. Slave resistance as well as British, papal, and international anti-slavery pressure all played a role.

In Belgium, the division between Catholics and Protestants influenced public debate on Belgium’s Catholic king and his imperialist plans in Africa. Having held shares in the Belgian trading company’s activities in the Lower Congo, Leopold II was given control of Congo at the Berlin Conference of 1884–1885, with the expectation that he would keep it a tax-free zone of free trade for all international powers. The “Congo Free State” became the emperor’s private fief. Leopold II hosted the Brussels Conference of 1889–1890, during which Cardinal Lavigerie fostered international commitment to the suppression of slavery and the slave trade in Africa. The conference’s act was signed by all the main European powers, as well as by the Ottoman emperor, the Persian shah, and the sultan of Zanzibar. Some articles called specifically on non-European rulers to suppress slavery in their territories. The anti-slavery actions of Ottoman, Persian, and Zanzibari rulers were mentioned explicitly.⁶⁶ This signaled a first step in the direction of internationalism that would characterize international anti-slavery policy in the following century.⁶⁷ But at the Brussels Conference, this was hardly a sign of openness toward the positions and priorities of non-European powers.

The Colonial Occupation of Africa and the Invisibilization of African Abolitionists

When abolitionism became the official doctrine of the world’s most powerful empires slavery did not end, but the strategies of anti-slavery activists went from proclaiming the slaves’ humanity to denouncing the slavers’ inhumanity. European empires asserted their right to intervene on grounds of their abolitionist credentials. Initially, they put pressure on African rulers, who started passing abolitionist legislation. Some African rulers criticized the Atlantic slave trade but neither joined global abolitionism nor developed separate abolitionist movements analogous to those that opposed Atlantic slavery in Euro-America.⁶⁸ But others signed abolitionist treaties with Europe’s empires, primarily Britain.⁶⁹ Treaties focused on abolishing slave exports from Africa while leaving intact slave ownership within Africa.

In North Africa, since the 1810s Britain had signed treaties with the rulers of Egypt, Tripoli, Tunis, and Algiers (all subjects of the Ottoman caliph) and the sultan of Morocco. These treaties required that captured Christian enemies be treated as prisoners of war and that local rulers stop pirates from engaging in the illegal slave trade. In Madagascar, the king of Imerina signed an abolition treaty with the representative of the British Crown as early as in 1817.⁷⁰ The Moresby Treaty with the sultan of Muscat and Zanzibar in Oman, signed in 1822, forbade the sale of slaves to European traders and gave the British navy power to stop and search ships in the Indian Ocean.⁷¹ In 1845, the Hamerton Treaty forbade all trade in slaves on the entire stretch of the East Africa coast controlled by the sultan. But clove production and other export commodities continued to rely on slave labor.⁷² Successive sultans of Zanzibar passed anti-slavery decrees in their territories.⁷³ Britain tried to use treaties all along the coast in order to insulate the African continent by forbidding the sale of enslaved Africans at their final point of departure. In 1838, a memorandum of the Slave Trade Department of the Foreign Office suggested extending the treaty system to cover all of Africa’s coastal line.⁷⁴ Some African rulers negotiated each clause of the treaties they signed and were selective. When King Gezo of Dahomey was asked to consider a British treaty on January 13, 1852, he accepted one single clause that committed him to ban the export of slaves from his dominions and refused to sign other clauses.⁷⁵ Hundreds of treaties were also signed with the rulers of small African polities that were scarcely known in Europe at the times.

The European legal abolitions that had implications for Africa were not far, chronologically, from the early African independent abolitions. It was not until 1833 that the British Empire abolished slavery everywhere in its dominions. Independent Liberia abolished slavery in its constitution of 1846, the same year as Ottoman Tunisia.⁷⁶ Abolitionism in Ethiopia developed gradually: some authors see early examples thereof already in the 16th century, but edicts abolishing the slave trade in the 19th century, and slavery itself in 1923, are better studied.⁷⁷ The French abolition of 1848 had direct consequences in Africa for Algeria, Senegal (Saint Louis, Gorée, and few fortified posts), Mayotte, La Réunion, and the île Maurice.⁷⁸ At a local level, small hubs of African abolitionism developed. The significance of their activities is progressively becoming clearer as new research is carried out on African abolitionism.⁷⁹

Christian ex-slaves who had been in contact with missions, were among the first Africans to champion slavery’s abolition in their own continent.⁸⁰ Evangelization in Africa was intense among ex-slaves and liberated slave children enrolled in missionary schools.⁸¹ In institutions such as the prestigious Fourah Bay College, Sierra Leonean teachers and preachers inspired some of the most influential West African humanitarians of the 18th and 19th centuries. Although these men lived under British colonial rule, their abolitionist strategies were distinct from those of mainstream British abolitionists. They would remain so, as black abolitionists distanced themselves from white missionary and colonial elites who posed as liberators but took on increasingly racist attitudes as imperialism intensified in the second half of the 19th century.

Some of the earliest abolitionists in Africa had been liberated by the British Navy and had joined missionary societies. In West Africa, Yoruba Samuel Ajayi Crowther was enslaved at 13 by Muslim raiders who attacked his town in 1821. He was resold six times and was bound to the Americas when he was freed and brought to Sierra Leone. He became one of the first graduating students at Fourah Bay College and was recruited by the Church Missionary Society for the 1841 Niger Mission that had both scientific and abolitionist aims. He became the first Anglican bishop in Africa.⁸² Like Crowther, James “Holy” Johnson was a Yoruba graduate of Fourah Bay. His parents had been rescued from slavery. He became superintendent of all Church Mission Society (CMS) missions in interior Yorubaland, abolitionist, and critic of anti-African attitudes in European missionary orders. Many mission-educated recaptives, as well as African elites like David Asante from Akwapem (Ghana in the early 21st century) struggled against African slave-owning elites and European alleged abolitionists who did not want anti-slavery to destabilize established hierarchies.

In the Gold Coast, Fante intellectuals and political elites had started developing abolitionist ideas in the mid-19th century.⁸³ Like in the West Indies, local political and intellectual leaders had been involved in the development of the first local newspapers. Through their writings in the local press, they influenced public debate on the forms of slavery and slave trade practiced by different societies in the subregion and on the strategies to counter these.⁸⁴ Also on the East African coast, liberated slaves and their descendants, for example, in the settlements of Freretown and Rabai, played a leading role in facilitating the emancipation of captives and fugitive slaves in the second half of the 19th century.⁸⁵ Zanzibari enslaved concubines networked with Friends missionaries to demand that slavery be completely abolished in their region and that British local administrators did not delay the emancipation of concubines.⁸⁶

Not only Protestant but also Catholic missions influenced the development of African abolitionist ideas. Some of Lavigerie’s doctor catechists, following medical training in Malta, left as auxiliaries of the White Fathers. Joseph Gatchi, who had been born around 1865 in Kano, had been captured in a slave raid and resold multiple times until he was bought by a White Father in an Algerian market in 1875. In a letter to Lavigerie that he wrote from Central Africa in April 1891, he described a trip he made in the surroundings of Kibanga, where he was based: “Please allow me to entitle my trip as follows: at the redemption of slaves.”⁸⁷ Adrien Atiman, a Songhay born in Tindirma west of Timbuktu and a contemporary of Gatchi, followed the same trajectory. The best known among the doctor catechists of slave descent, Atiman was a practicing doctor all his life. While he did not develop a public abolitionist agenda, he was pragmatically involved in the liberation and conversion of slaves in the context of the missionary stations where he worked.⁸⁸

These are but a few examples of thousands of Africans who, having experienced enslavement and emancipation directly or by witnessing the plight of others, developed firm anti-slavery convictions. As far as we are aware, they did not start named and institutionalized local, let alone global, abolitionist movements. But their actions helped local enslaved persons to free themselves from slavery. The institutions that had contributed to their liberation encouraged them to act as native auxiliaries but did not promote their autonomous leadership largely due to racist stereotypes. African humanitarians lost trust in official abolitionism and continued to undermine slavery in a rhizomic manner, below the radar and often against the direct orders of European-led institutions that posed as liberators. Furthermore, after colonial occupation, the political interests of the colonial administration resulted in tensions with missions. Missionaries perceived to undermine the authority of collaborating African chiefs in their efforts to support slaves were reprimanded and forced to stop.

The anti-slavery commitment of Africans, primarily liberated slaves and intellectuals, started a quiet ideological revolution on the continent. Some of them operated within colonial and missionary abolitionist networks. Others were, or became, critical of imperialist abolitionism that allowed European colonization to advance.⁸⁹ These individuals witnessed the colonial occupation of Africa. Some, like Daniele Sorur Pharim Den (c. 1860–1900), pronounced themselves against both African slavery and European racism. Born in a Dinka village in what is South Sudan in the early 21st century, enslaved at 13, and redeemed by missionary Daniele Comboni, he joined the Comboni order and devoted his life to Christianization, education, and the eradication of slavery in Africa.⁹⁰ Around the time of his death, Europe’s “civilizing mission” resulted in the occupation of the African continent.

From Imperialist Abolitionism to Postcolonial Anti-Slavery

Imperialist abolitionism reached its apex at the Brussels Conference. The establishment of Leopold II’s power in what he had named the Congo Free State was one of its catastrophic consequences. However, this was also a time when interconnected nongovernmental anti-slavery organizations, such as the British and Foreign Anti-Slavery Society, had started campaigning at a global level. The horrors of Leopold II’s management of his private fief in the Congo were denounced by activists like missionary Alice Seeley Harris, who traveled in the Congo and documented Leopold II’s abuses through a photographic campaign aimed at turning global public opinion in favor of reform at the beginning of the 1900s. Edmund Morel founded the Congo Reform Association in 1904 to raise awareness of mass exploitation and violence in Leopold’s Congo. This international activism contributed to bringing an end to the “Congo Slave State,” as Morel had dubbed it, in 1908 when the region became a Belgian colony. These campaigning methods would continue to inform nongovernmental international anti-slavery in the 21st century.

Abolitionism is as abolitionism does. Abolitionist ideology justified the colonization of Africa by Europe and served the purposes of white supremacist rhetoric that advocated European intervention to save African victims from Barbaric slavers in the name of civilization and religion. This replaced the emphasis on an ethics of equality and reciprocity that had informed the initial stages of the struggle for the abolition of the slave trade, in which Protestant Evangelical sects had played a leading role. Now Europe’s superiority, often expressed in racialized terms, and responsibility toward domestic industrialization and imperial commercial interests were prioritized. The speeches of Europe’s prime ministers in the 1880s and 1890s, men like the Marquess of Salisbury in London and Jules Ferry in Paris, highlighted economic and “civilizational” arguments in favor of colonization. Within approximately two decades, the entire African continent (with the exception of Ethiopia and Liberia) was integrated into Europe’s most powerful empires.

When European empires became the governments responsible for implementing abolitionism in Africa, their commitment to African freedom weakened. The task was too big. They needed cheap labor for the construction and maintenance of colonial infrastructure and the support of African elites for the imposition of their new order. But African elites would mobilize labor from among those formerly enslaved and their descendants. Thus, the colonial administration turned a blind eye to the continuation of hierarchies rooted in slavery and co-opted precolonial slavery for its own ends. Everywhere in Africa the colonial administration hesitated to enforce its own anti-slavery laws. For most of the continent, European abolitions were the first attempt to legally ban slavery in African societies. But the limited efficacy of colonial abolitions is well documented.⁹¹ Administrators occasionally suppressed the anti-slavery actions of missionaries. It was mainly enslaved men and women who made emancipation happen. But they often opted for trajectories out of slavery that allowed them to bury a painful and shameful past. Their tactics were influenced by cultural approaches that encouraged (self-)censorship of matters considered shameful. Slavery was one of these.⁹²

Two general trends changed global abolitionist strategies in the early 20th century: secularization and internationalism. As a result of the combined action of these two processes, the main tension straining across international abolitionism in the 20th century was not opposition between religious and secular anti-slavery approaches but antagonism between individual empires and international governmental institutions. Abolitionism turned out to be a double-edged sword for Europe’s colonial empires, which scrutinized each other’s anti-slavery actions. Concurrently, national and international nongovernmental organizations became influential players, prefiguring the “guardian” role of the League of Nations.⁹³ The League after 1920, and the United Nations after World War II, developed anti-slavery committees that monitored the anti-slavery practices of colonial empires. These committees put pressure on colonial governments to eradicate the slave trade and prosecute slave owners who abused and tortured their slaves.

Under colonial rule persons of slave descent continued being classified as slaves through biological reproduction and the enduring ideological legitimacy of pro-slavery rationales that justify the slave owners’ domination and the slaves’ subordination.⁹⁴ Legal abolition denied official recognition of the status of “slave,” but in some countries more than others, slavery continued not only “to exist, but [to be] actively and openly practiced.”⁹⁵ Slavery has been peculiarly resilient in the most stratified African societies. The latter include Fulani (Peul), Tuareg, Moors, and Songhai societies that have been described as structured into caste-like strata.⁹⁶ Enslaved persons occupied the bottom layer of steep social hierarchies, a layer that was further internally stratified. Particular labels or group names corresponded to each stratum and substratum of society. Manumitted slaves could become “freed slaves” (specific vernacular designations existed for this status) but could not join the social strata of the freeborn. They continued to be stigmatized locally and in the diaspora.

During the anti-colonial struggle and after decolonization the legacies of slavery within recently independent nations were silenced by African politicians who fought against colonial regimes and saw slavery as a politically destabilizing issue that could divide their new nations. In the words of Africa’s world-renown abolitionist, the Mauritanian parliamentarian Biram Dah Abeid, in Mauritania, and other West African Sahelian countries, the African leaders who struggled for independence bequeathed abolitionism and class struggle to his generation.⁹⁷ In Mauritania, Mali, and Niger, the discontent of persons of slave descent gained momentum during civil conflicts like the Spanish Sahara conflict in Mauritania and the movements known as “Tuareg Rebellions” in Mali and Niger. These circumstances brought together men who felt excluded in their own countries and societies. Slave descendants who had mobilized on national war fronts and rebel guerrillas gained awareness of the widespread nature of their problem. They acquired a language to claim full citizenship as discriminated subgroups within their respective ethnic constituencies. Some of the main anti-slavery organizations developed within their ranks. In the words of a former Nigérien combatant of slave descent:

I grew up at the home of my masters who are Tuareg Kel Eghlel from the second nomad group of Abalak. . . . I lived with them as their slave until I turned 23. Then I migrated to Libya, where I joined a camp of rebel combatants who were training in armed fight. In Libya I found some Tuareg from my region of Abalak, who told me that they had decided to take arms against Niger because the state ignored our rights. Having escaped slavery, I too felt that my rights had been violated and I decided to join the group.⁹⁸

National anti-slavery movements like the Initiative for the Resurgence of Abolitionism (IRA, Mauritania), Timidria (Niger), Temedt (Mali), and many others, developed in the last forty years to fight against slavery’s resilience where the impact of abolitionist ideas has been weakest and slavery continues to be ideologically defensible among local elites. In the 21st century, African anti-slavery nongovernmental organizations protest against the survival of slavery and the cruelty of slavers in their societies. In Mauritania, these movements are at the forefront of national politics: Biram Dah Abeid was elected to parliament in 2018 and ran for president in 2014 and 2019 on an abolitionist and human rights agenda. In a speech given on the occasion of his candidature for presidential elections at the Constitutional Council of Nouakchott on April 29, 2019, he denounced the vitality of “primitive slavery” in Mauritania:

Men and women of Mauritania! At the origin of my determination is the desire to reverse the hideous observation that our state has become the executioner of part of its people and also the last standing breeding ground for primitive slavery in the world.⁹⁹

The fight against resilient slavery and descent-based discrimination colors African politics at multiple levels. Mauritania is exceptional in the extent to which it dominates struggles at the top of national politics. But activism at the level of local and municipal elections is also common. In the late 1990s and early 2000, Gando in northern Benin formed organizations such as Idi Waadi (What We Want Has Taken Place) led by Gando from Nikki, Djanati (Peace Has Finally Come) in Kandi, and Semmee Allah (The Force of God) in Kalalé. These Gando-centered identity politics resisted against former elites who treated the Gando as slaves (“it’s time to cut the rope of slavery,” as an interviewee explained to Eric Hahonou).¹⁰⁰ With decentralization in the 1990s, some local Gando leaders won municipal elections in districts where the demographic majority self-identified as Gando.

In Mali and Niger anti-slavery nongovernmental organizations have been putting pressure on their governments to pass anti-slavery legislation and enforce these laws. They lobby against slavery and discrimination based on slave descent. Their members and paralegal staff also benefit from support by some representatives of “customary chiefdoms” (chefferies traditionnelles).¹⁰¹ In Niger, the local chiefs most committed to undermining slavery have been the children of slave concubines, like Almou Wangara, who gave witness at the trial of Hadijatou Mani. Some of these men experienced the suffering of their mothers in their childhood and empathized with them. Anti-slavery activities have also taken the form of spontaneous grassroots mobilization. In many West African regions, informal runaway slave associations provide safety nets for trafficked, marginalized, or exploited persons of slave descent seeking refuge and help in urban or rural areas.¹⁰² At the local level, associations of specific subgroups classified as slaves or slave descendants (such as Saafaalbe Hormankoobe at the border between Senegal and Mauritania) are increasingly common in West Africa.¹⁰³

West African anti-slavery activists act at the national, subregional, and international levels. Internationalism has been central to their strategies in two main forms: connections with supporters in the diaspora and with international organisations like the United Nations and Anti-Slavery International). At the national level, their strategies vary according to the political circumstances of their respective governments and the ideological visions of their leaders. Islamic clerics (often of slave descent) are usually asked to deliver a blessing for participants in their meetings and events; an important strand of their arguments consists of demonstrating that Islam condemns slavery and its contemporary legacies.¹⁰⁴ However, religious rationales are not foregrounded in their official statements. These anti-slavery movements emphasize egalitarian notions of citizenship and invoke universal human rights against lingering pro-slavery attitudes in their countries.

In French-speaking West Africa anti-slavery movements formed the G5 Sahel Anti-Slavery Network. In 2022, this network included the main West African anti-slavery organizations. They mobilized collectively to put pressure on the Malian government to pass a law that criminalizes slavery and to stop the revival of pro-slavery in the Kayes region in the 2010s. Here, descendants of slave owners have been attacking the persons and property of slave descendants. They humiliated them in public and denied them access to public services. They threatened, beat, and killed anti-slavery activists. The G5 Sahel Antislavery network organized conferences and made public statements against these dynamics.¹⁰⁵ Biram Dah Abeid (Mauritania), Ali Bouzou (Niger), Ilguilas Weila (Niger), Ibrahim Ag Idbaltanat (Mali), Rhaichatou Walet (Mali), Amadou Diemdioda Dicko (Burkina Faso), Alioune Tine (Senegal) and others in Chad, Guinea, and Benin are but some of the main West African abolitionists who acquired visibility and influence. Ali Bouzou, leader of Timidria and the executive secretary of the G5 Sahel Antislavery Network, sees their structures as best suited to act as auxiliaries of the state in slavery-related matters.¹⁰⁶ Their increasingly official and public role was confirmed at an anti-slavery forum organized by Biram Dah Abeid and hosted by the president of the Islamic Republic of Mauritania at the Palace of Congress of Nouakchott in March 2022¹⁰⁷—an event that would have been unthinkable only a few years earlier when Biram was imprisoned and the IRA was operating clandestinely. These movements do not focus on “modern slavery.” They struggle to effectively eradicate the modern legacies of historical forms of slavery that Europe’s imperialist abolitionism of the late 19th century failed to suppress.

Discussion of the Literature

Almost as soon as abolitionism became an official doctrine, books on its history began to appear. One of the earliest histories of British abolitionism is Thomas Clarkson’s The History of the Rise, Progress, and Accomplishment of the Abolition of the African Slave Trade by the British Parliament published in two volumes in 1808. Christopher Brown and Seymour Drescher, among others, provide useful introductions to the vast and diverse literature on abolitionism that followed Clarkson’s book.¹⁰⁸ Already in the 1930s and 1940s this literature split between books that celebrated the accomplishments of imperialist abolitionists, such as Reginald Coupland’s The British Anti-Slavery Movement, and books that took an anti-colonial stance.¹⁰⁹ The most important examples of the latter approach are C. L. R. James’s The Black Jacobins and Eric Williams’s Capitalism and Slavery, both by Caribbean authors.¹¹⁰

James asserted the significance of the Haitian Revolution as a non-Western-led revolutionary anti-slavery movement with global repercussions. It had an enormous intellectual and political impact, as attested by the texts included in the Black Jacobins Reader edited by Charles Forsdick and Christian Høgsbjerg.¹¹¹ Williams’s book was also highly significant and polarizing. It interpreted British abolitionism as the outcome of capitalist self-interest. Williams’s theses have been hotly debated. Critical works include Seymour Drescher’s Econocide and Eltis and Engerman’s reassessment of the economic significance of slavery for the British economy, trade, and industry.¹¹² Others agree with most of Williams’s arguments and highlight the ways that certain British actors benefited from abolitionism, as they had benefited from the earlier profits of slaving and the slave trade. This debate focuses on the economic causes and consequences of abolition.¹¹³

David Davis and Seymour Drescher studied Euro-American abolitionism, inquired into its causes, and explored the strategies of the main Western abolitionists.¹¹⁴ Robin Blackburn and Christopher Brown contextualized British abolitionism in other major historical dynamics. In The Overthrow of Colonial Slavery, Blackburn sees the anti-colonial and anti-slavery struggles as intertwined and mutually influencing;¹¹⁵ in Moral Capital, Brown zooms in on one particular anti-colonial struggle—the American Revolution—and argues that it provided a moral incentive to focus on abolitionism as a way to rebuild the empire’s reputation.¹¹⁶ Derek Peterson’s edited volume Abolitionism and Imperialism in Britain, Africa and the Atlantic was published in the aftermath of the 2007 200th anniversary of the British abolition of the slave trade, which was accompanied with extensive self-congratulatory celebrations in the United Kingdom.¹¹⁷ It focuses on the contested legacies of British abolitionism. Works on French and continental European abolitionism include Nelly Schmidt’s important collection of primary sources, accompanied by substantial critical essays; Oliver Pétré-Grenouilleau’s study of abolitionism in France, Portugal, and Switzerland; and Giulia Bonazza’s study of abolitionism in Italy.¹¹⁸

Manisha Sinha’s The Slave’s Cause: A History of Abolition book sheds light on the roles played by blacks and women of all colors in advancing “the slaves’ cause.”¹¹⁹ Other authors have argued that historians should acknowledge and research the contributions of enslaved persons and their descendants to the demise of slavery. Markus Rediker and Peter Linebaugh’s The Many-Headed Hydra: The Hidden History of the Revolutionary Atlantic and Julius Scott’s The Common Wind: Afro-American Currents in the Age of the Haitian Revolution are the best-known examples of this approach.¹²⁰ Gelien Matthews’s Caribbean Slave Revolts and the British Abolitionist Movement focuses on how British abolitionists used the three main Caribbean slave revolts of the early 19th century (at Barbados in 1816, Demerara in 1823, and Jamaica in 1831–1832) to push the public opinion in favor of immediate emancipation.¹²¹ Richard Anderson and Henry Lovejoy’s edited volume Liberated African and the Abolition of the Slave Trade focuses on the agency of freed slaves. Seymour Drescher and Pieter Emmer edited the volume Who Abolished Slavery? that contrasts authors who prioritize the role of slave revolts with authors who prioritize the role of imperial abolitionists (the editors support the latter’s arguments).¹²²

The question addressed by Drescher and Emmer is oversimplistic: as Manisha Sinha demonstrated, “slave resistance lay at the heart of the abolitionist movement,” and it is impossible to understand abolitionism without contextualizing it in various forms of contemporary slave resistance, including the abolitionist strategies of the formerly enslaved.¹²³ Abolitionists of all kinds, however, should not be idealized but subjected to the same critical scrutiny as all other historical actors. Waibinte Wariboko’s study of Afro-Caribbean abolitionist missionaries and their activities in southern Nigeria is a case in point, and sheds light on understudied networks.¹²⁴ It builds on previous works that paid attention to the positionality of different groups involved in abolition, such as Howard Temperley’s White Dreams, Black Africa: The Antislavery Expedition to the Niger and Lamin Sanneh’s Abolitionists Abroad: American Blacks and the Making of Modern West Africa.¹²⁵ The idea that abolitionism does not have the same meaning everywhere and for everyone but has been experienced and operationalized differently by different groups is also at the heart of Hideaki Suzuki’s edited volume Abolitions as a Global Experience.¹²⁶

The study of Islamic approaches to abolition and abolitionism is so broad that it can be seen as a subfield divided between authors who tend to argue that an abolitionist stance is possible, or even well attested, in Islam (the work of Rudolph Ware and Bernand Freamon is a good illustration of these positions) and others who pay more attention to the resilience of slavery in Muslim societies.¹²⁷ Yusuf Hakam Erdem’s Slavery in the Ottoman Empire and Its Demise, 1800–1909, Ehud Toledano’s Slavery and Abolition in the Ottoman Middle East, and William Gervaise Clarence-Smith’s Islam and the Abolition of Slavery are major overviews.¹²⁸ Bruce Hall and Ghislaine Lydon’s review article gives a clear and comprehensive introduction to the problem of slavery in Islamic law (2016).¹²⁹ The 2010s saw the publication of several important monographs on official approaches to abolition in Islamic states of the 19th and 20th centuries. All published in 2013, the books by Chouki el Hamel (Morocco), Ismael Musah Montana (Tunisia), and Zekeria Ould Ahmed Salem (Mauritania) are key examples of geographically focused but conceptually wide-ranging contributions to these debates.¹³⁰ Paul Lovejoy’s Jihad in West Africa during the Age of Revolutions looks at Atlantic slavery and abolitionism from the perspective of jihadist Islamic movements in West Africa that were not abolitionist but opposed the Atlantic slave trade.¹³¹

In this very extensive literature, there are gaps. Although abolitionism is often cited as one of the main, if not the main, genuinely global movement, its developments in Africa and Asia are scarcely studied. For Africa, the works of Adiele Afigbo, Femi Kolapo, José Lingna Nafafé, and other Africanist historians mentioned in this article are still exceptions. Critical editions of sources in non-European languages should be published to advance the analysis of non-European abolitionst and anti-slavery discourses. The worldwide triumph of abolitionism is a story we tell ourselves on the basis of a teleological reading of history that sees slavery as destined to end.¹³² But we know little about abolitionism in Africa, Asia (particularly China), Oceania, and parts of Latin America.¹³³ While these regions were never insulated from global interactions, their indigenous forms of slavery were not identical to slavery in Euro-American cultures.¹³⁴ The historiography of abolitionist movements in these regions focuses primarily on European anti-slavery activities and is based on European sources. It presupposes that when Europe abolished slavery in other parts of the world, colonized societies became abolitionist. This conclusion is unwarranted, and more research is needed, especially research that uses sources in indigenous languages. African, Chinese, and Indian abolitionist movements are still poorly understood. The few extant studies available attest to the originality and distinctiveness of these diverse abolitionisms.¹³⁵