Columbus’s discovery of America in the last decade of the fifteenth century can be seen as an unexpected consequence of the failure of the Crusades in their Eastern Mediterranean campaigns between the eleventh and thirteenth centuries. Columbus and the Catholic Monarchs of Spain, Queen Isabella I and King Ferdinand II, who were blessing his sea expedition, were inspired by the ideology of the Crusades. They were hoping to discover new sea routes to the Indies which would enable Spain (basically Catholic Europe) to outflank their great Oriental rival whose power was rising in Asia, Africa, and Europe.
While Western Christendom was still recovering from the failure of the Crusades, they were hit by the fall of Constantinople (the Byzantine Empire) to the Ottomans in 1453. Aeneas Silvius Piccolomini (later Pope Pius II) described the fall of Constantinople as “a second death to Homer and a second destruction of Plato.” The Catholic intellectual and political establishment in Europe was gripped by the fear of being under siege, and there was a new urgency for protecting Europe and finding new sea routes to the Indies and other lands. Isabella I and Ferdinand II completed their conquest of the Nasrid Kingdom of Granada in 1492 and in the same year Columbus set sail for exploring the Atlantic to discover new sea routes and lands.
In a document addressed to Isabella I and Ferdinand II, Columbus promised to convert the regions that he discovered during his expedition to the holy faith. He was a believer in end times and the rise of Antichrist who would rescue the Holy Land.