Abstract
The Age of Discovery and Expansion saw the emergence of Castile as a colonial power. Alexander VI, in his Papal Bull of May 4, 1493, granted the Kings of Castile dominion over the Indies and decreed that | "an imaginary demarcation line he drawn 100 leagues west of the Azores and the Cape Verde Islands; that Spain could claim all lands found or to he found West and South of the demarcation line towards the Indies, provided they had not been occupied by any other Christian prince." | The Bull also imposed on Spain one supreme obligation: "to spread the gospel and draw the pagans into the church of Christ." The following year, the Treaty of Tordesillas between Spain and Portugal fixed the demarcation line in the Atlantic to 370 leagues west of the Cape Verde Islands and established Spain's title to "all lands found or to be found west of the demarcation line." The Papal Bull and the Treaty of Tordesillas gave Spain a legal basis for sending expeditions to the unknown parts of the world by a westward route and, subsequently, paved the way for Ferdinand Magellan's expedition to the Western Pacific.