Portuguese ships first reconnoitre the Nigerian coast

Between 1469 and 1475 a Lisbon merchant, Fernão Gomes, held the lease of the Guinea trade from King Afonso V of Portugal under a contract requiring his captains to explore one hundred leagues of coastline annually beyond Sierra Leone. By 1471 Gomes' seamen had reached the Costa da Mina, and probably in the two succeeding years they penetrated into the Bight of Benin, gained knowledge of its principal rivers, and discovered that slaves could be bought there. The sixteenth-century historian Antonio Galvão attributed the first Portuguese voyage through the Bight of Benin to Ruy de Sequeira in 1472.