Henry the Navigator.

In the middle of the fifteenth century Prince Henry of Portugal subsidized several expeditions down the western coast of Africa. In 1455 Henry, who was known as "the Navigator," appealed to Pope Nicholas V to confer the title to all of the countries that his agents discovered on these voyages to Portugal. In return Henry promised to spread the Christian faith to nonbelievers and bring them under the authority of the Church. Nicholas, anxious to expand the religion beyond Europe, issued a papal bull called the Romanus Pontifex. This decree gave Portugal title to those African "provinces, islands, ports, districts and seas . . . which have already been acquired and which shall be acquired in the future." The Pope warned that any European monarch who encroached upon or interfered with Portugal's rights would be excommunicated from the...