Last of the four viceroyalties that Spain created to govern its New World colonies.
Established in 1776 as means of decentralizing rule in the Spanish empire, it controlled an area previously administered by the Viceroyalty of Peru and included what is now Argentina, Uruguay, Paraguay, and Bolivia. Successive viceroys defended the territory against encroachment by Portugal and Britain and helped Buenos Aires become a flourishing outpost of the Spanish empire. Salted meat from the cattle ranches of the interior, exported to meet the demand for cheap food for slaves, brought unprecedented wealth to the colony. In 1810 the Creoles created a provisional junta and sent the viceroy into exile. See also New Granada ; New Spain .