The decision to plan and execute the Conquest of the Desert was probably catalyzed by the 1872 attack of Cufulcurá and his 6,000 followers on the cities of General Alvear, Veinticinco de Mayo, and Nueve de Julio, where 300 criollos were killed, and 200,000 heads of cattle taken. In the 1870s, the Conquest of the Desert was a controversial campaign by the Argentine government, executed mainly by General Julio Argentino Roca, to subdue or, some claim, to exterminate the native peoples of the south.