Ferdinand Magellan, born in 1480 in northern Portugal, led the first expedition around the earth and named the Pacific Ocean (peaceful sea). He convinced Charles I of Spain (Charles V of the Holy Roman Empire) to fund an expedition to find the 'East Indies,' or the "Spice Islands," where Indonesia's modern day Maluku Islands are located.
Magellan was an avid explorer even before his famous journey. He sailed to India and the far East, amongst other places. However, he was wrongly accused for trading illegally with the Moors and he also quarreled with King Manuel I of Portugal over funds for a journey to the Spice Islands. He therefore sought employment and allegiance with Spain over his native country. The two Iberian countries competed fiercely during the Age of Exploration.
The 5 ships, the Trinidad, San Antonio, Concepcion, Victoria, and Santiago, set off in September 1519. Only one returned in September 1522, with only 18 of the original 270 crewmembers, Magellan not among them. He had been killed in an altercation with Filipino natives when he stopped at the Island of Mactan. His journey for the Spice Islands brought him many places around the world, including Chile and Guam. When the lone shipVictoria returned, it was commanded by Juan Sebastián del Cano.
Along with being credited as the first to circumnavigate the earth and naming the Pacific Ocean, he also discovered what is now called the Strait of Magellan and named the Tierra del Fuego. Additionally, Magellanic Clouds in space are named such as his crew is believed to be the first to view them.
Sources: Wikipedia, Geography.about.com, Biography.com, Enchanted Learning.com