Fro the first Muslim invasions of the Iberian Peninsula in the 8th century to the last decades of the15th century, the Christian rulers of the various kingdoms of these land fought to retake the land in the name of Christ. As the centuries progressed more and more of the lands were retaken through the "Reconquista."
By 1492, the monarchs Queen Isabella of Castile & Leon and King Ferdinand of Aragon (both descended from the king of Leon) had married, uniting their joint kingdoms into what would become Spain and completed the Reconquista by eliminating Granada, the last Muslim stronghold in Western Europe.
One of the benefits of the final actions of the Reconquista was the "liberation" of land, properties and much of the wealth of the Muslims. A large portion of these riches now came into the hands of the King and Queen, just in time to fund a risky venture to discover a shorter trade route to India under the command of one Cristóbal Colón.
In 1493, Cristóbal Colón returned to Spain claiming to have found a new route to Asia and the "Indies." It would take several more voyages by multiple European Explorers to eventual establish that Colón had actually discovered a hitherto unknown land-"the New World." The centuries long Reconquista to retake the Iberian peninsula for Christianity now lead to the opening of entire "new" continents to colonization and religious conversion.