Angola was a colony of Portugal for more than 400 years from the 15th century. Demands for independence picked up momentum during the early 1950s, with the principal protagonists including the MPLA, founded in 1956, the National Front for the Liberation of Angola (FNLA), which appeared in 1961, and the UNITA, founded in 1966. After many years of conflict that weakened all of the insurgent parties, Angola gained independence on 11 November 1975, after the Carnation Revolution in Portugal, which overthrew the Portuguese regime headed by Marcelo Caetano.