In 1481, Diogo was appointed by
John II as captain of a fleet consisting of nine
caravels and two ships with 600 soldiers and 100 masons and carpenters. They were sent, along with the necessary stone and other materials, to construct a fortress called
São Jorge da Mina at the
Gulf of Guinea in the
Portuguese Gold Coast colony. This became the best-known exploit of his long life. They chose a favourable defensive position for the fort, and construction was practically complete after only 20 days, in spite of resistance from the native population. With the fortress finished, contacts were established with the local population to establish trade. Diogo de Azambuja sent the fleet back to
Lisbon with word that the mission has been successfully accomplished, and he remained behind as captain of the fortress with a force of 60 soldiers. He held this post until 1484. The fortress is now known as "Elmina Castle", or the "Elmina Slave Castle". ==Courtier==