Both the British and French established trading posts on the Guinea-Bissau coast; the Portuguese claims were not realised until 1884.
Control over the interior was not established until 1915, even then resistance held out until 1936.
The PAIGC (the party supporting independence in Guinea-Bisseau and the Cape Verde Islands) began in 1956. It resorted to guerrilla warfare in 1961 due to mounting repression by the colonial authorities. The Portuguese were unable to contain the struggle.
By the early 1970's approximately three quarters of the country had been liberated. The Portuguese armed forces had been confined to Bissau, the capital, and a number of smaller towns and military posts.
Efforts were made to revive the war-torn agricultural sector by peasants in the liberated areas; political and material support was given to the peasants.
In 1973 independence was unilaterally declared. The new government was recognised by the majority of countries around the world, but the Portuguese only withdrew several months later after Caetano was toppled.
Amilcar Cabral was the leader of the revolutionary struggle. He was assassinated by the Portuguese before independence was granted, by doing this they thought they would be able to force a split in the nationalist movement but they failed.
His successor was Luiz Cabral, his half brother.
The PAIGC was committed to liberating Guinea-Bissau and Cape Verde and also to uniting the two.
In 1980 President Luiz Cabral was overthrown in a coup orchestrated by Prime Minister Vernardo Vieira. The consequence of this coup was a rift between the mainland and Cape Verde and ended the unified political party although they were brought together later due to the intervention of Presidents Machel of Mozambique and Santos of Angola.
Ever since the country has been ruled by Vieira.
Guinea-Bissau is destined to remain one of the world's poorest nations due to its high density of population.