Christopher Columbus commanded the first European fleet to establish a permanent colony in America. Popularly thought to have discovered America, his expedition established the "New World" in the European mindset.
Columbus's early life is mostly unknown. However, he was definitely an experienced sailor and a devout Christian.
Columbus wrote a "Book of Prophecies", in which he predicted the impending return of Christ after a successful crusade which he planned to lead. To finance this project and win support, he planned to establish a new trade route to the Spice Islands (mostly modern Indonesia), avoiding the Ottoman Empire by going through the Ocean Sea -- the Atlantic Ocean, which he believed to be the same as the Pacific Ocean. (This was five years before Vasco da Gama successfully reached India by going around the southern tip of Africa.)
When Columbus presented this proposed new trade route in many European courts, he faced much opposition. Educated men had known since ancient Greece that the world was round, and Eratosthenes had even calculated a reasonably correct circumference. So, it was well known that the combined Atlantic and Pacific Oceans would be much too broad for Columbus to sail across - any fleet would starve long before reaching Asia.
Finally, however, Ferdinand and Isabella of Spain gave Columbus three small ships, suitable for cruising along the shore of islands. Columbus set sail west in 1492 by way of the Canary Islands, reaching San Salvador (now in the Bahamas) on on October 12, 1492.