On May 26, 1880, after the Battle of Alto de la Alianza, the Chilean army occupied the Tacna province. Under the terms of the treaty, Chile was to occupy the provinces of Tacna and Arica for ten years, after which a plebiscite was to be held to determine the region's sovereignty. Tacna remained under Chilean control for 50 years, during which Chilean groups and authorities lead a campaign of Chilenization in an attempt to persuade the local population to abandon their Peruvian past and accept Chilean nationality.