The explorer and cartographer Amerigo Vespucci (March 9, 1454 - February 22, 1512) was the first person to demonstrate that the New World discovered by Christopher Columbus in 1492 was not the eastern appendage of Asia, but rather a previously-unknown "fourth" continent. It is widely believed that the continents of North and South America (and, by extension, the United States of America) derive their name from the feminized Latin version of his first name (see Naming of America).
He played a senior role in two voyages which explored the east coast of South America between 1499 to 1502. On the first of these voyages he discovered that South America extended much further(the Indies). Vespucci's voyages became widely known in Europe after two accounts attributed to him were published between 1502 and 1504. In 1507, Martin Waldseemüller produced a world map on which he named the new continent America after Vespucci's first name, Amerigo. In an accompanying book, Waldseemüller published one of the Vespucci accounts, which led to criticism that Vespucci was trying to usurp Christopher Columbus' glory . However, the rediscovery in the 18th century of other letters by Vespucci, primarily the Soderini Letter, has led to the view that the early published accounts were fabrications, not by Vespucci, but by others.
In 1508, after only two voyages to the Americas, the position of chief of navigation of Spain (piloto mayor de Indias) was created for Vespucci, with the responsibility of planning navigation for ocean voyages. He died of malaria on February 22, 1512 in Seville, Spain.
Two letters attributed to Vespucci were published during his lifetime. Mundus Novus (New World) was a Latin translation of a lost Italian letter sent from Lisbon to Lorenzo di Pierfrancesco de' Medici. It describes a voyage to South America in 1501-1502. Mundus Novus was published in late 1502 or early 1503 and soon reprinted and distributed in numerous European countries. Lettera di Amerigo Vespucci delle isole nuovamente trovate in quattro suoi viaggi (Letter of Amerigo Vespucci concerning the isles newly discovered on his four voyages), known as Lettera al Soderini or just Lettera, was a letter in Italian addressed to Piero Soderini. Printed in 1504 or 1505, it claimed to be an account of four voyages to the Americas made by Vespucci between 1497 and 1504. A Latin translation was published by the German Martin Waldseemüller in 1507 in Cosmographiae Introductio, a book on cosmography and geography, as Quattuor Americi Vespuccij navigationes (Four Voyages of Amerigo Vespucci). In 1508, King Ferdinand made Vespucci Pilot Major of Spain at a huge salary and commissioned him to start a school for navigators out of his home to standardize and modernize navigation techniques used by Spanish sea captains exploring the world. Future luminaries such as Magellan learned at his knee, and Vespucci even developed a rudimentary method of determining a fairly accurate determinant for finding longitude (which only more accurate chronometers could later improve upon).
In the 18th century three unpublished familiar letters from Vespucci to Lorenzo de' Medici were rediscovered. One describes a voyage made in 1499-1500 which corresponds with the second of the "four voyages". Another was written from Cape Verde in 1501 in the early part of the third of the four voyages, before crossing the Atlantic. The third letter was sent from Lisbon after the completion of that voyage.`
Some have suggested that Vespucci, in the two letters published in his lifetime, was exaggerating his role and constructed deliberate fabrications. However, many scholars now believe that the two letters were not written by him but were fabrications by others based in part on genuine letters by Vespucci. It was the publication and widespread circulation of the letters that led Martin Waldseemüller to name the new continent America on his world map of 1507 in Lorraine. Vespucci used a Latinised form of his name, Americus Vespucius, in his Latin writings, which Waldseemüller used as a base for the new name, taking the feminine form America. (See also Naming of America.) Amerigo itself is an Italian form of the medieval Latin Emericus (see also Saint Emeric of Hungary), which through the German form Heinrich (in English, Henry) derived from the Germanic name Haimirich.
The two disputed letters claim that Vespucci made four voyages to America, while at most two can be verified from other sources. At the moment there is a dispute between historians on when Vespucci visited mainland the first time. Some great historians like German Arciniegas and Gabriel Camargo Perez think that his first voyage was done in June 1497 with the Spanish Juan de la Cosa. Little is known of his last voyage in 1503–1504 or even whether it actually took place. Vespucci's real historical importance may well be more in his letters, whether he wrote them all or not, than in his discoveries. From these letters, the European public learned about the newly discovered continent of the Americas for the first time; its existence became generally known throughout Europe within a few years of the letters' publication.
According to historians such as Martín Fernández de Navarrete, Germán Arciniegas and Gabriel Camargo Pérez, the first voyage of Amerigo Vespucci took place in 1497, probably in a trip organized by King Ferdinand, who wanted to clarify if the mainland of the landmass was far away from the island of Hispaniola, which had been discovered by Columbus.
The captain of this company, which set sail in May 1497 was Vicente Yañez Pinzón, captain of the Niña on Columbus's first voyage, and may have included Juan Diaz de Solis. Accompanying Vespucci was pilot and cartographer Juan de la Cosa (the then-famous captain who had sailed with Columbus in 1492). According to the first letter of Vespucci, they reached land at 16 degrees latitude, probably on the coast of La Guajira peninsula in present-day Colombia or the coast of Nicaragua. They then followed the coastal land mass of central America before returning to the Atlantic Ocean via the Straits of Florida between Florida and Cuba.
In his letters, Vespucci described this trip, and once Juan de la Cosa returned to Spain, a famous world map, depicting Cuba as an island, was produced. About 1499–1500, Vespucci joined an expedition in the service of Spain, with Alonso de Ojeda (or Hojeda) as the fleet commander. The intention was to sail around the southern end of the African mainland into the Indian Ocean. After hitting land at the coast of what is now Guyana, the two seem to have separated. Vespucci sailed southward, discovering the mouth of the Amazon River and reaching 6°S, before turning around and seeing Trinidad and the Orinoco River and returning to Spain by way of Hispaniola. The letter, to Lorenzo di Pierfrancesco de' Medici, claims that Vespucci determined his longitude celestially on August 23, 1499, while on this voyage. However, that claim may be fraudulent, which could cast doubt on the letter's credibility.
The last certain voyage of Vespucci was led by Gonçalo Coelho in 1501–1502 in the service of Portugal. Departing from Lisbon, the fleet sailed first to Cape Verde where they met two of Pedro Álvares Cabral's ships returning from India. In a letter from Cape Verde, Vespucci says that he hopes to visit the same lands that Álvares Cabral had explored, suggesting that the intention is to sail west to Asia, as on the 1499-1500 voyage. On reaching the coast of Brazil, they sailed south along the coast of South America to Rio de Janeiro's bay. If his own account is to be believed, he reached the latitude of Patagonia before turning back, although this also seems doubtful, since his account does not mention the broad estuary of the Río de la Plata, which he must have seen if he had gotten that far south. Portuguese maps of South America, created after the voyage of Coelho and Vespucci, do not show any land south of present-day Cananéia at 25° S, so this may represent the southernmost extent of their voyages.
After the first half of the expedition, Vespucci mapped Alpha and Beta Centauri, as well as the constellation Crux, the Southern Cross. Although these stars had been known to the ancient Greeks, gradual precession had lowered them below the European skyline so that they were forgotten.
On his return to Lisbon, Vespucci wrote in a letter to de' Medici that the land masses they explored were much larger than anticipated and different from the Asia described by earlier Europeans and, therefore, must be a New World, that is, a previously unknown fourth continent, after Europe, Asia, and Africa.