Juan Manuel José Domingo Ortiz de Rozas y López de Osornio (30 March 1793 – 14 March 1877), nicknamed "Restorer of the Laws", was an Argentine politician and army officer who ruled Buenos Aires Province and briefly the Argentine Confederation. Born into a wealthy family, Rosas independently amassed a personal fortune, acquiring large tracts of land in the process. Rosas enlisted his workers in a private militia, as was common for rural proprietors, and took part in the disputes that led to numerous civil wars in his country. Victorious in warfare, personally influential, and with vast landholdings and a loyal private army, Rosas became a caudillo, as provincial warlords in the region were known. He eventually reached the rank of brigadier general, the highest in the Argentine Army, and became the undisputed leader of the Federalist Party.
In December 1829, Rosas became governor of the province of Buenos Aires and established a dictatorship backed by state terrorism. In 1831, he signed the Federal Pact, recognising provincial autonomy and creating the Argentine Confederation. When his term of office ended in 1832, Rosas departed to the frontier to wage war on the indigenous peoples. After his supporters launched a coup in Buenos Aires, Rosas was asked to return and once again took office as governor. Rosas reestablished his dictatorship and formed the repressive Mazorca, an armed parapolice that killed thousands of citizens. Elections became a farce, and the legislature and judiciary became docile instruments of his will. Rosas created a cult of personality and his regime became totalitarian in nature, with all aspects of society rigidly controlled.