Who really sailed around the world first, Magellan or Elcano?

Neither one alone: Magellan planned and began the voyage, and Elcano finished it. The expedition, funded mostly by Spain's King Charles I, set out hoping to find a western route to the Spice Islands, since Portugal controlled the eastern route under the Treaty of Tordesillas. Magellan, a Portuguese captain sailing for Spain, planned it and led it at first. Juan Sebastián Elcano completed it, and together they produced the first circumnavigation of the Earth.

The cost was staggering. Magellan expected the sea between South America and the Spice Islands to be small and thought he could cross it in three or four days. The crossing took three months and twenty days. Most of the men suffered from scurvy, and Pigafetta, a crew member who kept a journal, reported that of 166 men who embarked on the crossing, 19 died and twenty-five or thirty fell ill.

The voyage was violent, too. At Guam, Magellan sent a raiding party that burned forty or fifty Chamorro houses and killed seven men. He did not make it home: on Mactan in the Philippines, Lapu-Lapu refused his demand to accept the king of Spain as ruler, and Magellan's forces were driven back and defeated. Magellan died in the battle. Elcano, who had himself taken part in a mutiny and had embarked seeking the king's pardon for previous misdeeds, led the one surviving ship home.

When the Victoria returned in September 1522, only 18 of the original 270 men were on board. The crew also made an odd discovery: at Cape Verde, their date was one day behind the local date, even though they had recorded every day. They had lost a day by travelling west, the same direction as the sun appears to move.