What came to be known as the Age of Discovery was a product of increasing competition of European political entities for territory, trade routes, religious expansionism -- in effect, the spread of Christianity -- and the natural instinct of some to explore the unknown. Europeans, especially the Spanish and Portuguese, were keenly interested in exploring the unknown parts of the world. Little was actually known about the physical world beyond their frontiers, and the Iberian Peninsula represented the geographical westward boundary of the known world. Eastward expansion was out of the question given the military strength of the Ottoman and Mongol empires.
The competition to claim the unknown world was intense. The glory of discovery was a powerful motivating force, but the promise of unknown wealth and the spread of Christianity were key to ensuring the financial support for exploration of the ruling monarchs of the time. The resulting occupation and division of the Western Hemisphere as a result of the Age of Discovery would have devastating effects on the native populations of what came to be known as the Americas for hundreds of years.