He called it the South Sea.

Wading into it waist deep, he waved his sword in the air and took possession of it for his royal master, the King of Spain.

This was in 1513.

Seven years later, in 1520, Magellan, a Portuguese seaman in the service of the Spanish king, sailed through the Straits of Magellan and entered the same great ocean, which he called the Pacific.

Thence northward and westward he sailed day after day, week after week, and month after month, until he reached the Philippine Islands.