Portuguese Ships Enter "The Sea Of The South"
Having sailed from the Atlantic Ocean through the passage that came to be known as the Straits of Magellan, three ships under the command of native Portuguese explorer Ferdinand Magellan entered "The Sea of the South" on November 28, 1520.
Thus the first westward crossing of the Pacific Ocean was launched.
The fleet reached the island of Guam on March 6, 1521 after a voyage so remarkable for its calm that the explorers called the ocean "Pacific." Setting foot on land, the crew that had been reduced to eating leather enjoyed fresh food for the first time in 99 days.
The journey resumed. The Santiago was sent down the coast on a scouting expedition and was wrecked in a sudden storm. All of its crew survived and made it safely to shore. Two of them returned overland to inform Magellan of what had happened, and to bring rescue to their comrades. After this experience, Magellan decided to wait for a few weeks more before again resuming the voyage.
At 52°S latitude on October 21, the fleet reached Cape Virgenes and concluded they had found the passage, because the waters were brine and deep inland. Four ships began an arduous trip through the 373-mile (600 km) long passage that Magellan called the Estrecho (Canal) de Todos los Santos, ("All Saints' Channel"), because the fleet travelled through it on November 1, or All Saints' Day. The strait is now named the Strait of Magellan. Magellan first assigned Concepcion and San Antonio to explore the strait, but the latter, commanded by Gómez, deserted and returned to Spain on November 20. On November 28, the three remaining ships entered the South Pacific. Magellan named the waters the Mar Pacifico (Pacific Ocean) because of its apparent stillness. Magellan was the first European to reach Tierra del Fuego just east of the Pacific side of the strait.
Wikipedia: Ferdinand Magellan
Today In History: Crossing The Pacific