From Tony Horwitz, A Voyage Long and Strange:
"In a final insult [to Columbus], the most enduring honor of all went to a fellow Italian who had befriended Columbus in his last years. 'He is a very honorable man and always desirous of pleasing me,' wrote Columbus, ever a poor judge of character, 'and is determined to do everything possible for me.' The man's name was Amerigo Vespucci.
"A well-connected Florentine merchant and a scion of the Medicis, Vespucci moved to Seville and outfitted fleets crossing the Atlantic. He sailed to the Indies several times between 1499 and 1502, under both Spanish and Portuguese auspices, and claimed to be a great navigator. But his true genius was for hype and self-promotion.
" 'I hope to be famous for many an age,' he wrote, in one of the embellished accounts he gave of his voyages. Vespucci invented some episodes and lifted others from Columbus's writing. Unlike the Admiral, though, he showed great flair for lubricious tales designed to titillate his European audience.
"Native women, he claimed, were giantesses--'taller kneeling than I am standing'--and impervious to age and childbearing, with taut wombs and breasts that never sagged. ... Best of all, they were 'very desirous to copulate with us Christians,' Not surprisingly, Vespucci's account became an instant best seller. ...
"[Unlike Columbus, who never gave up his belief that the lands he discovered were part of Asia], Vespucci referred to the [South American] region as 'a new world.' unknown to 'our ancestors,' ... In 1507, a year after Columbus's death, the German geographer Martin Waldseemuller published a text and map adding a 'fourth part' to the known world of Europe, Asia, and Africa. 'I see no reason why one should justly object to calling this part Amerige,' Waldseemuller wrote, 'or America, after Amerigo, its discoverer, a man of great ability.' His revised world map had 'America' engraved next to a landmass roughly resembling Brazil.
"Waldseemuller later changed his mind and dropped the name from a subsequent edition. But 'America' was reprised in 1538 by the great cartographer Gerard Mercator, who applied it to continents both north and south."