According to the information you provided, the navigator you are talking about should be the following one:

Ferdinand Magellan (full name: Ferdinand Magellan, Portuguese: Fern? o de Magalh?es; Spanish Fernando de Magallanes, spring 1480 - April 27, 1521), explorer, navigator, colonist[1]. Portuguese explorer for the Spanish government.

Magellan’s circumnavigation of the world was a product of the Western Renaissance and the beginning of a new route. If I have to say a famous saying, combined with his experience and theory, it can be combined into one sentence: The earth is round.