At the Battle of Mactan, Ferdinand Magellan, a Portuguese navigator in command of a Spanish expedition to traverse the globe, was killed by warriors of datu Lapulapu. Ruy López de Villalobos came in Leyte and Samar in 1543 and named them Las Islas Filipinas in honor of Philip II of Spain, who was Prince of Asturias at the time. When his father, Charles I of Spain (who also reigned as Charles V, Holy Roman Emperor), abdicated the Spanish throne on January 16, 1556, Philip became King of Spain. Philip was in Brussels at the time, and his return to Spain was delayed until 1559 due to northern European politics and warfare.Soon after his return to Spain, Philip ordered an expedition to the Spice Islands, with the stated goal of "discovering the islands in the west." Its true purpose was to conquer the Philippines for Spain.

Despite a series of storms and mutinies, the expedition successfully passed through the Strait of Magellan into the Mar del Sur, which Magellan renamed the "Peaceful Sea" (the modern Pacific Ocean). The expedition reached Guam and, shortly after, the Philippine islands. There Magellan was killed in the Battle of Mactan in April 1521. Under the command of captain Juan Sebastian Elcano, the expedition later reached the Spice Islands.