Basques formed a minority ethnic group whose diaspora had a significant impact on the history of colonial Latin America. Basques from the four Spanish or peninsular Basque territories—the Lordship of Vizcaya, the provinces of Álava and Guipúzcoa, and the Kingdom of Navarra—migrated to the New World in significant numbers; the French Basques were also prominent in the Atlantic, particularly in the Newfoundland fisheries. The population density of the Basque Atlantic valleys, which was the highest of any region in Spain, was an important factor that encouraged emigration. And, in response to demographic pressure, in the second half of the 15th century most villages and towns adopted an impartible inheritance system that compelled non-inheriting offspring to seek their fortunes outside the country. Castile was the immediate choice for the Basque émigré, but after 1492 America gradually became an attractive destination. Outside their home country, their unique language and sense of collective nobility (hidalguía universal) were to become two outstanding features of Basque cultural identity. The Basques’ share of total Spanish migration to the New World increased significantly in the second half of the 17th century. By the 18th century they were one of the largest and most influential peninsular regional groups in America. The typical Basque émigré was a young, single man aged between fifteen and thirty. In the New World they left their mark in economic activities that their countrymen had developed in their homeland for centuries: trade, navigation, shipbuilding, and mining. Furthermore, Basques’ collective nobility and limpieza de sangre (blood purity) facilitated their access to important official positions.