On this day in history,...

...in 1520, Portuguese explorer Ferdinand Magellan, leading a Spanish expedition, sailed out of the strait that now bears his name and entered a vast and previously uncharted body of water. Struck by the unexpected calmness of the sea after the treacherous storms of the Atlantic and the strait, Magellan named it the "Mar Pacífico" – the Peaceful Sea.

The expedition had spent weeks navigating the dangerous and narrow passage at the southern tip of South America, which Magellan believed was the long-sought western route to the Spice Islands. Upon exiting the strait, the crew found a wide expanse of open ocean and unusually favorable weather conditions, which contrasted sharply with the turbulent seas they had faced earlier.

Although Magellan would not survive the journey—he was killed in the Philippines in 1521—his voyage was the first to demonstrate the full expanse of the Pacific Ocean and connect it to the Atlantic through a navigable route. The naming of the Pacific was not only a symbolic moment but also a key milestone in the geographic understanding of global ocean basins.

What makes this episode even more remarkable is that Magellan’s naming of the Pacific is the only instance in history in which a single explorer has given a lasting name to an entire ocean. Other ocean names—like the Atlantic, Indian, or Arctic—evolved from mythological, geographical, or classical sources, but none were bestowed in such a direct and singular way.

Today, the Pacific Ocean is recognized as the largest and deepest on Earth, playing a crucial role in global climate, atmospheric circulation, and plate tectonics. Magellan’s impression of its calmness was circumstantial—modern oceanographers know it can be as violent as any other sea—but the name has endured for over five centuries.

Sources

•    Pigafetta, Antonio. The First Voyage Around the World (translated by Lord Stanley of Alderley), 1874.
•    Bergreen, Laurence. Over the Edge of the World: Magellan’s Terrifying Circumnavigation of the Globe. HarperCollins, 2003.
•    Encyclopaedia Britannica. “Discovery of the Strait of Magellan.” https://www.britannica.com/biography/Ferdinand-Magellan
•    History.com. “Magellan Reaches the Pacific.” https://www.history.com/this-day-in-history/november-28/magellan-reaches-the-pacific