What is "montoneros"

Montoneros was an Argentine leftist urban guerrilla group, active during the 1960s and 1970s. The name is an allusion to the 19th century cavalry militias who fought for the Partido Federal during the Argentine Civil Wars.

After Juan Perón's return from 18 years of exile and the 1973 Ezeiza massacre, which marked the definitive split between left and right-wing Peronism, the president expelled the Montoneros from the Justicialist party in May 1974. The group was completely destroyed during the Dirty War.