In 1453, the Fall of Constantinople to the hands of the Ottomans was a blow to Christendom and the established business relations linking with the east. In 1455, Pope Nicholas V issued the bull Romanus Pontifex reinforcing the previous Dum Diversas (1452), granting all lands and seas discovered beyond Cape Bojador to King Afonso V of Portugal and his successors, as well as trade and conquest against Muslims and pagans, initiating a mare clausum policy in the Atlantic.Daus 1983, p. 33. The king, who had been inquiring of Genoese experts about a seaway to India, commissioned the Fra Mauro world map, which arrived in Lisbon in 1459.Bagrow 1964, p. 72.
