The decision of planning and executing the Conquest of the Desert was probably triggered by the 1872 assault of Calfucurá 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 1872 the indigenous leader Calfucurá and his 6,000 followers attacked the cities of General Alvear, Veinticinco de Mayo and Nueve de Julio.