After the decease of don Henry, the illustrious promoter of maritime discovery, the progress of the Portuguese along the coast of Africa received a considerable check, as the attention of Alphonso V. was wholly engrossed by his quarrels with the court of Castile. Ever since the year 1453 considerable importations of gold had been made to Portugal from the coast of Africa, but the efforts to extend discoveries farther to the south appear to have been remitted about the same time. In 1469 a merchant named Fernando Gomez farmed the Guinea trade from king Alphonso for the yearly rent of live hundred ducats, and bound himself at the same time to extend the discovery of the coast five hundred leagues to the south during the period of his exclusive privilege. During this time were discovered the islands of Fernando Po, Prince's Isle, St. Thomas, and Annobon; the last being within a degree and a half of the equator.

No detailed relations remain of the several voyages in which these discoveries were effected; but it appears that during the period which elapsed between the death of don Henry in 1463 and that of king Alphonso, which took place in 1481, the navigations of the Portuguese along the coast of Africa had made a great advancement; comprehending the whole coast of Guinea, with its gulfs named the Bights of Benin and Biafra> the adjacent islands, and the shore extending southwards to the northern frontier of the kingdom of Congo.