On September 20, 1519, five ships carrying about 270 men left Sanlucar de Barrameda at the mouth of the Guadalquivir, under the command of Ferdinand Magellan, a Portuguese captain sailing for Spain. The object was to reach the Moluccas, the Spice Islands, by going west, and thus to give Spain a claim to them under the Treaty of Tordesillas. He did not live to finish it.
Magellan was 39 or thereabouts, a Portuguese nobleman who had served in India and Morocco, had been passed over at court, and had taken his case to Charles I of Spain. His argument was that the Moluccas lay on the Spanish side of the line and that a strait through South America would reach them. Spain gave him five ships, the Trinidad, San Antonio, Concepcion, Victoria and Santiago, and most of the money came from Christopher de Haro, a Flemish merchant.
It nearly ended in mutiny. At San Julian in Patagonia, in April 1520, three of the five captains rose against him while the fleet was wintering; Magellan put down the rising, executed one captain, marooned another, and left the third. A ship was lost. Then in October 1520 he found the passage: a strait of about 350 miles of channels and currents, and it took 38 days to get through it.
What came after was worse than what came before. The Pacific crossing took 99 days with no fresh food, and the crew ate rats, sawdust and the ox hides on the rigging, and about 19 men died of scurvy. They reached Guam in March 1521 and then the Philippines, where Magellan involved himself in a local war on the island of Mactan and was killed on April 27, 1521.
One ship got home. Juan Sebastian Elcano took the Victoria west across the Indian Ocean, round the Cape of Good Hope, and into Sanlucar on September 6, 1522, with 18 men of the original 270 and a cargo of cloves worth more than the whole expedition had cost. The voyage proved that the earth was one ocean, that it was bigger than anyone in Europe had calculated, and that the date line problem was real: the survivors had lost a day.