The Earlier Republican Period

Over the course of the Republic, the plebeian tribunes’ rights expanded, gradually extending beyond their core functions of assisting members of the plebs against patricians and magistrates (see magistracy, roman) of the Roman populus as a whole, and presiding over the plebs’ own legislative and electoral assemblies (see comitia). Central was the tribunes’ right of giving assistance (auxilium), which entitled them to protect Roman citizens—personally—from perceived injustices, but not beyond the first milestone from the city. From this developed the right of veto (intercessio) on most official acts in Rome, including the passage of legislation in all the popular assemblies and even decrees of the Senate (see senate, regal and republican period), as well as the tribunes’ powers of arrest and prosecution (see coercitio). All the tribunes’ rights ultimately rested on their peculiar status, ritually established at the creation of the office (traditionally for 493 bce: Broughton, MRR Ι‎ 15), as sacrosanct, that is, inviolable as to their persons; it was the plebs themselves who guaranteed that inviolability of their leaders during their year in office (Livy 2.33.1 and 3, 3.55.10). The tradition that legislation of 449 bce (Livy 3.55.1–7, 13–15, see Valerius Poplicola Potitus, Lucius and Horatius Barbatus, Marcus) then confirmed and regularized the essentially sacral tribunicia potestas (and, according to Livy, extended the sacrosanctity to aediles and other representatives of the plebs) smacks of the legalism of a later age and runs counter to the observed fact that in the historical Republic only the tribunes enjoyed special protection.

The Middle Republic

The plebs in essence formed a separate state within the Roman state (see already Livy 2.44.9, elaborated by Mommsen, Röm. Staatsr. III 145), and the tribunes as their officials saw only slow integration into the larger political system of the Roman people (populus). Development of the tribunes’ powers and prerogatives is notoriously hard to trace, especially because of the frequency of obvious anachronism in sources for the earlier Republic, especially Livy and Dionysius (7) of Halicarnassus, who freely retroject conditions more appropriate to the first half of the 1st century bce to the more distant past. Yet the grand political compromise of 367 bce (see Licinius Stolo, Gaius and Sextius Sextinus Lateranus, Lucius), which enabled plebeians to hold the consulship and thus be reckoned as nobles (see nobilitas), must have dented to a certain degree the tribunes’ dedication to use their powers primarily for the interests of their class and accelerated implementation of the tribunicia potestas in actual senatorial politics. Livy in his annalistic account (see annals and annalists) of the Third Samnite War (298–291 bce; see Samnium) may illuminate this evolution, for in 294 he portrays a patrician successfully asking plebeian tribunes for their auxilium in the matter of obtaining a disputed triumph (Livy 10.37.9–12). If accepted—Livy previously in his narrative had pictured patricians making several unsuccessful appeals—this notice implies early recognition of the plebs’ protectors as efficacious on behalf of all of Rome’s citizens, and as such relevant to both the administration and politics of the state as a whole.¹ There is also a firm tradition that, shortly afterward in 287 bce, a lex Hortensia deemed legislation passed in the plebs’ assembly under the presidency of tribunes (known as plebiscites) to be binding on the whole Roman people (Gai. Inst. 1.3), even without assent by the Senate (patrum auctoritas), which previously was required. This law provides good evidence for the indispensability, already by the early 3rd century bce, of the tribunes to the smooth functioning of the Roman state. Evidently they had become the most important vehicle for moving routine legislation, as well as laws that were needed in a hurry—such as the authorization in late 327 to extend the imperium of the cos. Q. Publilius Philo into the next year (Livy 8.23.11–12), the first such grant.

In the mid-2nd century bce Polybius, in his overview of Rome’s (unwritten) constitution, could observe that “the plebeian tribunes are always obligated to carry out the resolve of the people (demos), and especially regard their will,” and as such have earned the fear of the Senate (6.16.5). The annalistic record for the middle Republic amply confirms Polybius’s analysis of the aims of tribunician power, which now also included the protection of accepted custom and precedent in constitutional matters (mos maiorum). Indeed, in the Republican period, plebeian tribunes never seem to have achieved the full status of magistrates of the Roman People, nor is there evidence of an attempt to make the office part of the Republican cursus honorum. Nor for the first three centuries of the Republic did status as an ex-tribune qualify an individual for membership in the Senate, though (oddly) tribunes technically were empowered to convoke and preside over that body (Gell. NA 14.8.2; see Livy 22.61.6 and 27.5.14–19 for reported instances from the years 216 and 210 bce). Archival usage in Livy makes clear that, prior to 166 bce (when his account gives out), the Senate could not give direct orders to plebeian tribunes; rather, it had to instruct a magistrate of the Roman people to negotiate with them. Indeed, it was not until at least the mid-2nd century bce that tribunes had an expectation of admission to the Senate by virtue of having held their office. That came thanks to a lex Atinia (Gell. NA 14.8.2) of uncertain date, but certainly no earlier than c. 180 bce, when official letters from ranking magistrates of the Roman people still took care to note that they were issued on behalf of both the tribunes and the Senate (see RDGE 34, 38, 39, and contrast RDGE 4, from c. 140 bce) as separate entities, and probably after Livy’s account drops off in 166 bce. The admission of ex-tribunes to the Senate no doubt proved consequential in assimilating these anomalous officials to Rome’s proper magistrates (e.g., by the mid-1st century bce they too had received magisterial attendants), and before long the Senate dropped the formalities of negotiation (for which see e.g., Livy 45.35.4 for 167 bce) and treated directly with them.² Even the tribune’s right of intercessio experienced new constraints. Notably—and somewhat ironically—a Gracchan plebiscite of 123 bce (see Sempronius Gracchus, Gaius) prohibited tribunes from exercising their right of veto over the Senate’s arrangement of provinciae for incoming consuls (Broughton, MRR ΙΙ‎ 514).

The Late Republic

In 81 bce Sulla as dictator, as part of a more general reform of the Roman administrative system, sought definitively to deregularize and weaken the plebeian tribunate by (apparently) barring incumbents from further political office and limiting their ability to move legislation freely, perhaps insisting on the Senate’s prior approval for plebiscites (as was the situation before 287 bce); significantly, he left their defensive power of intercessio intact, which he clearly viewed as vexatious but must have had no practical way to eliminate (sources in Broughton, MRR II 66). After Sulla’s death (in 78 bce), his measures stirred up tribunes to mount fierce opposition, and by 70 bce they saw their rights and powers fully restored by a consular law (see MRR ΙΙ‎ 127 for the sources). In the 60s and 50s bce, the tribunes are notable for their willingness to use the full negative powers of their office in the service of the factional politics of the day, with relentless use of especially intercessio against the Senate’s decrees and legislation in all the assemblies, even the (largely ceremonial) lex curiata (see Cic. Fam. 1.9.25, 54 bce).

From Late Republic to Early Principate

Caesar, who in marching on Rome in 49 bce had ostentatiously represented himself as a champion of tribunician sacrosanctity, on his victory received an extraordinary grant of tribunicia potestas without having to hold the office of the tribunate itself (48 bce, awarded for life in 44 bce: Cass. Dio 42.20.3, 44.5.3). It was a startling measure—Caesar himself was a patrician—that (misleadingly) made tribunicia potestas seem roughly analogous to imperium, which since 327 bce could be extended or awarded to non-magistrates. Caesar’s adopted son and political heir Octavian (see Augustus) seized upon the precedent in his struggles as triumvir, procuring tribunicia potestas, or at least the tribunes’ sacrosanctity, for himself in 36 bce, which was apparently renewed or somehow modified in 30 bce (Cass. Dio 49.15.5–6, 51.19.6–7). Strikingly, in 35 bce Octavian managed to have tribunician inviolability, which by this time extended beyond protection from physical assault to encompass also verbal defamation, granted also to his half-sister Octavia as well as to his wife Livia (Dio Cass. 49.38.1). It was a clear sign that he intended even then to establish a dynasty. A final and consequential stage came in the constitutional settlement of 23 bce, when as Augustus he ostentatiously gave up his habit of holding consecutive consulships (an office which he had secured for each of the years 31–23 bce) in exchange for tenure of full tribunicia potestas (Cass. Dio 53.32.5–6). In the event he had it renewed each year for the rest of his life, a total of thirty-seven times (see Res Gestae 10.1), and used it to date individual years of his reign, counting from 23 bce. In addition to the sacrosanctity, this status gave Augustus the ability to convene and preside over the Senate, pass legislation in the assembly of the plebs (a privilege he exercised for his moral legislation of 18 bce: see marriage law, Roman), and veto public actions; it also effectively established him in the tribunate’s customary role as protector of popular interests. It is generally agreed that Augustus’s assumption in 23 bce of tribunician power, alongside enhanced imperium (established to command a super-province of all armed provinces, with the capability of intervening also in those nominally in the power of the Senate) definitively established the legal basis of his rule, and that of all subsequent emperors through the early 4th century ce. Tacitus in a capsule history of Augustus’s tribunicia potestas (Tac. Ann. 3.56) flatly considers it as a device for the emperor to assert his supremacy in the state without taking an invidious title such as king or dictator. The plebeian tribunate itself continued under Augustus and well into the imperial period (it is mentioned as late as the 5th century ce: Cod. Theod. 1.6.11 and 2.1.12), but it came firmly under the control of the emperors and already by the end of the 1st century ce the office could be deemed of little consequence (Plin. Ep. 1.23.1).

Significantly, after the settlement of 23 bce, Augustus arranged to have extraordinary tribunicia potestas conferred also on his successive sons-in-law. Agrippa married Augustus’s widowed daughter Iulia in 21 bce, and in 18 bce received tribunician power for five years (renewed in 13 bce), but died in 12 bce (Cass. Dio 54.12.2 and 28.1). Augustus in 11 bce then forced his stepson Tiberius to divorce and marry Iulia (Cass. Dio 54.35.4), and in 6 bce procured for him tribunician power for five years (Cass. Dio 55.9.4)—shortly before removing him to Rhodes (where Tiberius seems to have employed the coercive aspects of that power: Suet. Tib. 11) until 2 ce. On the death in 2 and 4 ce respectively of Lucius Iulius Caesar and Gaius Iulius Caesar (sons of Agrippa and Iulia whom Augustus adopted as heirs but never offered tribunicia potestas), Augustus now adopted Tiberius and secured for him tribunician power for ten years as well as imperium as a proconsul, each renewed in 13 ce (Cass. Dio 55.13.1 and Vell. Pat. 2.103, Cass. Dio 56.28.1). The practical effect of these grants was clearly to designate Tiberius as the successor to the principate and facilitate his future transition to the role (see Tac. Ann. 1.3 and especially 3.56); when Augustus died on 19 August 14, Tiberius was immediately able to act as de facto emperor. Augustus’s actions served as a productive precedent for a long series of subsequent emperors; in this way the tribunician power became a central element in the Empire’s institutional history.

Imperial Practice after Augustus

From the start, Tiberius as emperor stressed that tribunicia potestas provided a legal basis for his succession and rule (see Tac. Ann. 1.7); in inscriptions and coins that show his titulature, he reckoned the total years that he held the power by including also the period prior to his accession. That Tiberius would designate a political heir by this means was, as Tacitus makes clear (Ann. 3.57.1), positively expected, though he needed the Senate’s ratification to do so. In 22 ce Tiberius readily gained his request to that body that his son Drusus Iulius Caesar (born 13 bce) receive the tribunicia potestas, which sparked a consular’s adulatory suggestion (rejected by the emperor) that also on all monuments the year of their tenure of the distinction should replace the age-old system of consular dating (Tac. Ann. 3.56–57). In the event, Drusus would die in the next year, and Tiberius chose no one to replace him; in 31 ce the expectation of Lucius Aelius Seianus to fill the gap was exploited to lure him to a meeting of the Senate where he found himself instead denounced, arrested, and executed on the same day (Suet. Tib. 65.1, Cass. Dio 58.9.4–5). Though Gaius (1) “Caligula,” Claudius, and Nero on their accessions each received from the Senate the tribunicia potestas, none saw fit to designate a partner in the honor. Documentary sources show that the practice resumed only with Vespasian, who soon in his rule (on 1 July 71) secured for his son Titus tribunician power along with proconsular imperium to mark him as successor. Titus in turn, to mark the significance of the grant, gave up his title of princeps iuventutis.³ Marcus Cocceius Nerva did the same for Trajan when adopting him in October 97, and Hadrian for both Lucius Aelius Caesar and (after his death) Antoninus Pius on their adoptions in 136 and 138, respectively. After this time such designation became routine, so much so that Lucius Septimius Severus in 198 granted it to his son Marcus Aurelius Antoninus (1) “Caracalla” at age 10.

The Senate long remained in control of granting tribunicia potestas to emperors on their accession, as is shown by the cases of the usurpers Gaius Pescennius Niger Iustus and Decimus Clodius Septimius Albinus in 193–194, neither of whom claimed to possess it. In principle, emperors held tribunician power for life, but still had to have it renewed each year. Writing in the 3rd century, Dio (53.17.10) states that renewal came at the same time the plebeian tribunes took office, that is, 10 December. The actual record, despite many problems of detail, in general tends to confirm this statement; standard practice starting with Trajan (in 102) through at least Alexander Severus (reigned 218–235) was for emperors to date their first tribunician year from the day of their acclamation (dies imperii) until 9 December, and then define each succeeding year as running from 10 December to the following 9 December. What principles informed the change of tribunician date after 235 are harder to divine, for by 247 Philip I was using 1 January, and in 253, Valerian and his son Gallienus in their joint reign employed a date that fell between 15 August and 10 September. The practice of routinely noting an emperor’s iterations of tribunician power, and perhaps conferment of the grants themselves, ended with Constantine I (reigned 311–337).