Political map of South American nations 29 April 1879 (Conquest of the Desert): Through much of the 19th century, the Argentine Republic had maintained an uneasy existence with the tribal peoples of the southern Pampas (Indigenous peoples in Argentina). This ended in 1878 when Julio Roca, Argentine Minister of War and—from 1880—President, mobilized five military columns to march south, defeating most tribal resistance by late 1879 (Conquest of the Desert).