In 1520 the Portuguese explorer Ferdinand Magellan, searching for a passage that would lead from the Atlantic Ocean to the Pacific, discovered what was to be named the Straits of Magellan. At the time it was assumed that the land to the south of that passage, Tierra del Fuego, was part of this Unknown Southern Land. In 1578, after sailing through the Straits of Magellan, Sir Francis Drake was driven south and east by a gale, sailing south past Tierra del Fuego and proving that this was in fact a series of islands. Reaching 56°S, the furthest south recorded at this time, he reported that no land was visible. That stretch of sea is now known as the Drake Passage.