The Bijagós archipelago consists of 88 semitropical islands, only 23 of which are inhabited. Early settlement in the area that is now the nation of Guinea-Bissau started from the interior of Africa and moved westward, and it is believed that people arrived on the coast by 9000 B.C. Members of the broad Senegambian ethnic group who settled the islands became known as the Bijagós (Bissagos) people, a matriarchal and matrilineal society in which women choose their husbands and that is guided by female priests. Traditionally a hunter-gatherer society, they were famous for their almadias, large ocean-going canoes that could hold up to 70 people.

Picture of Samgambian ethnic group women

In 1446 the Portuguese captains Gil Eannes and Nuño Tristão landed the Bijago Islands of Guinea-Bissau to trade slaves, gold, ivory and pepper. In that year Portugal claimed the region as "Portuguese Guinea." The rivers of Guinea, governed by the Mali's tributary kingdom of Gabu, and the islands of Cape Verde and the Bijago Archipelagos were some of the first areas in Africa explored by the Portuguese. It was the strength of the kingdom of Gabu that kept the Portuguese from inhabiting the interior as they had done on the Cape Verde Islands.