The first known use of the name "America" dates back to 1507, when it appeared on a world map created by the German cartographer Martin Waldseemüller. On his map, the name is shown in large letters on what would now be considered South America, in honor of Amerigo Vespucci. The Italian explorer was the first to postulate that the West Indies did not represent Asia's eastern limit but were part of a previously unknown landmass. In 1538, the Flemish cartographer Gerardus Mercator used the name "America" on his own world map, applying it to the entire Western Hemisphere.