During the War of the Pacific, Chilean forces occupied great part of the south territory of Peru, including Tacna. The hostilities between both countries ended with the sign of the Treaty of Ancón in 1984, which between things established that the provinces of Tacna and Arica would stay under chilean control for 10 years, after which a plebiscite would be realized to decide the fate of both territories. However, this referendum never took place.