Amerigo Vespucci, also known as Americus Vespucci, was born in Florence, Italy, in 1454. As a child, he is said to have been interested in books, maps and star-gazing.
Thanks to his sugardaddy uncle, Vespucci received a first-rate education and was primed for a first-rate career in navigation.
In 1491, Vespucci moved to Seville, Spain, where he met Christopher Columbus not long after Columbus had returned from his first voyage to the New World. Vespucci then played a part in coordinating the supplies for the ships that would be used for Columbus' second and third voyages to the New World.
Vespucci's aim, as a supposedly skilled navigator and trader, was to find a faster and better way to sail to the Far East. To this end, Vespucci went on two or perhaps up to four voyages to Central and South America between 1497 and 1504 on behalf of the great New World colonising powers of Spain and Portugal. There is also the possibility, if his detractors are to be believed. that Vespucci never went on any voyage, and was no more than an arm-chair voyager.
After his 1501-1502 voyage (assuming he was indeed not a fraud), Vespucci had seen all he needed to conclude that Brazil, Venezuela and other places he had recently visited in no way resembled anything from Asia. Contrary to what Columbus thought, these lands, to the mind of Vespucci, formed part of a "New World."
Vespucci's lucky break and date with immortality was secured in the post-medieval year of 1507, when a pamphlet entitled "The Four Voyages of Amerigo" was published.
The Vespucci-friendly author of this pamphlet proposed that the newish South American lands that Amerigo had explored be named after him in his honour. Were it not unbecoming of him, Vespucci might have been tempted to drop to the ground and plant a loudly smacking kiss on the shoes of the pamplet writer.
Things didn't end there where names were concerned. There was an additional unexpected bonus for Vespucci -- who seems to have ridden one of the luckiest streaks in recorded history. Over time Vespucci's name came into use for North America in addition to South America.
The rest is history.
Other articles related to early explorers:
Christopher Columbus' Early Years
Columbus in the Years Leading up to 1492
Conditions on Early Ocean Voyages