Rosas, Juan Manuel de

Rosas, Juan Manuel de (1793-1877), Argentine dictator (1835-1852). Born in Buenos Aires, Rosas belonged to one of the city's prominent families. He amassed great wealth as a cattle farmer and beef exporter during the period when Argentina was establishing its independence from Spain. In 1827 he emerged as a military leader and champion of the country's conservative aristocracy, which favoured provincial autonomy, and opposed foreign influence and the liberal reforms advocated by the centralist Unitario faction, a group supporting the new governor of Buenos Aires Province, Juan Lavelle. From 1829 to 1832 Rosas was governor of Buenos Aires Province. In 1833 he led a successful campaign against the Native Americans of southern Argentina and two years later was reinstated as governor, a position he agreed to accept only on the condition that he was granted dictatorial powers. Supported by the Mazorca, an organization that terrorized his Unitario opponents, Rosas formed alliances with the leaders of the other Argentine provinces, winning for himself control of the nation's foreign affairs and external trade. He was a tyrant who established a large network of spies and secret police; by 1840, there were only a few who were prepared to risk opposing him. Rosas also ensured that his portrait was widely displayed in public places.

In 1843 he intervened in a civil war in neighbouring Uruguay, arousing fears of Argentine expansionism. Great Britain and France retaliated by imposing blockades on Buenos Aires (1838-1840 and 1845-1850), but Rosas persevered. In 1851 Justo Urquiza, a former supporter of Rosas, led a rebellion against him backed by Brazil and Uruguay. Ousted in 1852, Rosas spent the rest of his life in exile and died in England.