Like Columbus, Vespucci traveled to the New World (first in 1499 and again in 1502). Unlike Columbus, Vespucci wrote about it. Vespucci’s accounts of his travels were published in 1502 and 1504 and were widely read in Europe. Columbus was also hindered because he thought he had discovered another route to Asia; he did not realize America was a whole new continent. Vespucci, however, realized that America was not contiguous with Asia. He was also the first to call it the New World, or Novus Mundus in Latin, in his books.

With the discovery of this “New World”, maps were being redrawn all the time. No one really knew what land was where or how big it was. Because of this confusion, maps from the 1500s are incredibly inaccurate and contradictory. (They also often feature drawings of mythical sea creatures.) In 1507, a German cartographer named Martin Waldseemüller was drawing a map of the world–a very serious map. He called it the Universalis Cosmographia, or Universal Cosmography. Comprised of 12 wooden panels, it was eight feet wide and four-and-a-half feet tall. He based his drawings of the New World on Vespucci’s published travelogues. All countries were seen as feminine (like her lady Liberty today), so Waldseemüller used a feminine Latinized of Amerigo to name the new continents “America.” Cartographers tended to copy one another’s choices, so Columbus was left off the map. The rest is history.
(From Dictionary.com) - Millet