U.S. Department of State Background Note
The rivers of Guinea and the islands of Cape Verde were among the first areas in Africa explored by the Portuguese in the 15th century. Portugal claimed Portuguese Guinea in 1446, but few trading posts were established before 1600. In 1630, a captaincy-general of Portuguese Guinea was established to administer the territory. With the cooperation of some local tribes, the Portuguese entered the slave trade and exported large numbers of Africans to the Western Hemisphere via the Cape Verde Islands. Cacheu became one of the major slave centers, and a small fort still stands in the town. The slave trade declined in the 19th century, and Bissau, originally founded as a military and slave-trading center in 1765, grew to become the major commercial center.
Portuguese conquest and consolidation of the interior did not begin until the latter half of the 19th century. Portugal lost part of Guinea to French West Africa, including the center of earlier Portuguese commercial interest, the Casamance River region. A dispute with Great Britain over the island of Bolama was settled in Portugals favor with the involvement of U.S. President Ulysses S. Grant.
Before World War I, Portuguese forces, with some assistance from the Muslim population, subdued animist tribes and eventually established the territorys borders. The interior of Portuguese Guinea was brought under control after more than 30 years of fighting; final subjugation of the Bijagos Islands did not occur until 1936. The administrative capital was moved from Bolama to Bissau in 1941, and in 1952, by constitutional amendment, the colony of Portuguese Guinea became an overseas province of Portugal.
In 1956, Amilcar Cabral and Raphael Barbosa organized the African Party for the Independence of Guinea and Cape Verde (PAIGC) clandestinely. The PAIGC moved its headquarters to Conakry, Guinea, in 1960 and started an armed rebellion against the Portuguese in 1961. Despite the presence of Portuguese troops, which grew to more than