Between 1457 and 1459 the Portuguese court of Afonso V paid the monastery of San Michele in Isola the sum of 28 ducats for a copy of the map by Fra Mauro (active ca. 1430-ca. 1459/1464) perhaps the very one now in the Marciana Library. This commission would have been made in the context of the Portuguese court’s political diplomacy to establish, oversee, and promote expansion along the coasts of Africa. After the conquest of Ceuta, in North Africa, in 1415, Prince Pedro d’Aviz (1392-1449) had begun to add a political dimension to the first maritime navigations, devoting nearly ten years to visits to numerous courts and European cities, including Venice.
Prince Henry (1394-1460), known as “the Navigator”, had sponsored voyages beyond Cape Bojador and promoted commercial operations along the African coast as far as the Gulf of Guinea, which Fra Mauro identifies as Sinus Ethiopicus. Beginning about 1450, Afonso V (1432-1481) asserted political control over this expansion, establishing diplomatic relations especially with the Pontifical court so as to consolidate his territorial powers with specific papal bulls. During the reign of João II (1455-1495), around 1480, Diogo Cão (?-ca. 1486) and Bartolomeu Dias (ca. 1450-1500) first reached the coast of Congo and then, in 1488, the southern tip of Africa, demonstrating that the continent could be circumnavigated and that the Atlantic communicated with the Indian Ocean, precisely as Fra Mauro had foreseen.