The Angolan coast came under Portuguese control in the 16th century, and the interior was conquered during the late 19th century. Angolan nationalist groups waged a guerrilla war against the Portuguese during 1961-74, and on Nov. 11, 1975, Angola became an independent nation. With the withdrawal of Portugal, the three largest of the nationalist groups quickly fell out over the composition of the new government. The ensuing civil war caused most of the whites remaining in Angola to emigrate and brought the economic collapse of the country. The Soviet-supported faction, with the aid of Cuban troops, controlled the central government and the western portion of the country, while a South African supported faction (Unita) controlled much of the interior. An agreement ending the civil war was implemented in 1997 but soon fell apart. Hostilities continue, with the Unita forces controlling much of the country.