Americo Vespucio (using the Spanish form of Amerigo Vespucci’s name because it is closer to “America”), was held in the highest regard in his own day by merchant princes, kings, and geographers. His achievements were so esteemed that the continents of the New World were named after him. Later on, misled by false accusations and failure to understand the importance of his scientific work, the world for a time lost sight of his greatness. Today, Americo’s real stature may be seen. The purpose in what follows is to bring into proper relief, in relation to past misconceptions, his true contributions. It has been customary to think of him as secondary to Columbus. To make a correct evaluation, we must begin by remembering wherein Columbus failed.
There is no minimizing what Columbus did. He brought to Europe in 1493 definite news, which confirmed previous rumors, that land lay far to the west of the Mediterranean. Most important, he brought home his knowledge of sailing routes across the Atlantic in both directions—southwest from the Canaries with the trade winds, returning via the latitude of Gibraltar with the prevailing westerlies. Columbus gave Europe the keys to the Atlantic.
Columbus brought also the Great Delusion. He said the western land was Asia and believed that he had found a route to the Indies. His widely disseminated error focused the attention of all Europeans on the lands to the West, and his faulty claim led to the naming of the islands of the Caribbean as the West Indies.
The achievement of Columbus created serious problems for the rulers of Portugal and Spain. Had he found Asia? What were these lands to which he had opened the way? In anticipation of rounding the southern end of Africa in search for a sea route to India, Portugal had claimed the “islands opposite Guinea and beyond” (Treaty of Toledo, 1480), and under a Papal Bull of 1481, all “isles south to the Indies.” After learning in 1488 that the Cape of Good Hope had been rounded, Portugal was claiming everything south of the Canaries. If Columbus had indeed reached the Indies by sailing west, did any of the Portuguese claims apply to what he had found? By virtue of his voyage, did any of the western lands belong to Spain?
To settle the issue, the pope, two months after the return of Columbus, in May, 1493, divided the unknown regions of the world in half, reserving to Portugal everything east of a meridian line 100 leagues west of the Azores or Cape Verde Islands, and giving to Spain everything west of that line. The Portuguese were not satisfied, since the line was not far enough west to give them a land which they knew about—the Brazilian elbow, of which they were aware from maps in their archives. They threatened war. By the Treaty of Tordesillas, June, 1494, the Line of Demarcation between the possessions of Portugal and Spain was moved to 370 leagues west of the Cape Verde Islands, far enough to include the Brazilian elbow, which Andrea Bianco’s map of 1448 said was “1500 miles west of the Cape Verde Islands.”
Politics had added a new persistent problem to geography. How much of the lands west of the Atlantic belonged to each of the rival powers? In other words, how far west were they? Were they east or west of the Demarcation Line? The determination of longitude became something that would be welcomed at the royal courts. The work of Columbus raised the questions, but Americo Vespucio was the man who found all the essential answers. For details of Americo’s early life, various biographies will serve, such as Amerigo and the New World by German Arciniegras, Knopf, 1955, and Amerigo Vespucci, Pilot Major by Frederick J. Pohl, Columbia University Press, 1944. What Americo accomplished on his explorations is told in his letters to his Florentine patron, Lorenzo di Pier Francesco de’ Medici, and in his Letter to Soderini.
The Soderini Letter is a description of four voyages. There has been a dispute as to whether Americo actually made the First Voyage of 1497, which gave him a one-year priority over Columbus in sighting and landing on the coast of South America. Some have believed this voyage to be spurious, and that the false claim of priority for Americo was an attempt to steal credit from Columbus. Some have attempted to clear Americo of the charge of theft by denying the priority. Arciniegras believes Americo did make that First Voyage. The writers of this article feel that the reasons Arciniegras gives for accepting the First Voyage are weightier than those which have been advanced against it.
The Soderini Letter is garbled. It probably contains embellishments not from Americo’s pen. Inaccuracies inherent in transcription and proofreading undoubtedly crept in. No doubt in those days the modern Chamber of Commerce methods were equally in force and perhaps even less restrained. On the other hand, from external evidence and consistency, it seems best to accept the basic realities underlying all the Four Voyages.
The First Voyage has Americo in one of four consort ships making his landfall after 37 days from the Canary Islands, somewhere on the northern coast of South America, and following the coast to the northwest.
All along the coast, Americo observed many tribes of naked savages. Nakedness was extremely shocking to Europeans, and it is not surprising that the tone of Americo’s Letter to Soderini was frank and even ribald in its description of the natives. He told of their nakedness, skin color, sex habits, generosity in lending their women, their adeptness in swimming, their social customs, food, use of hammocks, etc. It was one of the most sensational tales ever narrated in Europe.
Americo said: “We entered into a harbor where we found a town built over the water like Venice; there were about twenty large houses after the fashion of huts based upon very thick piles, and they had their doors or house entrances in the form of drawbridges which they threw down from house to house.” From this, he named the region Venezuela (“Little Venice”).
From his landfall he followed the coast to the northwest for over 2000 miles to 16° North Latitude, therefore presumably to Honduras. Latitude was determined in those days by the elevation of Polaris, using an astrolabe or quadrant. It was determined within about one degree of accuracy at sea, and within about half a degree on land. For example, Columbus on his return in 1493 very accurately made his landfall at Lisbon.
Sailing away from the continental land to the northeast for seven days, Americo came to “many islands,” among them “Iti” (Haiti?). From these islands he may have gone north to the latitude of Gibraltar before turning east for “latitude sailing” to Cadiz. He thus may have seen some of the coastline of Florida and the Carolinas.
Eager to know more about the western lands, King Ferdinand looked around for a trustworthy man to ascertain the facts. He chose Americo because he was known to be interested in astronomy, cartography, and cosmography, because he was a business man of great probity, and because he was a friend of Columbus. Americo had been a partner of Berardi, the Medici agent in Spain, who had sunk his fortune in the First Voyage of Columbus and subsequently died insolvent. Partly because of his losses, Americo had “resolved to abandon trade, and to aspire to something more praiseworthy and enduring.” King Ferdinand asked him to go exploring “to aid in the discovery.”
It was as a geographer that he would report back to the king. He wrote to Soderini that he had spent as much time as he could with the pilots, learning to use their instruments and learning ship handling. He had graduated from a theoretical astronomer to a practical and experienced navigator.
King Ferdinand arranged a new expedition under the leadership of three mariners experienced in transoceanic voyages: Alfonso de Hojeda, Juan de la Cosa, and Americo Vespucio. Hojeda had been owner and master of the shipwrecked Santa Maria on the first voyage of Columbus, and had accompanied Columbus on his second voyage as a member of the Nina's crew. Americo’s appointment was in a twofold capacity as “one who knew cosmography and matters pertaining to the sea, and as a merchant.”
While the expedition when it set sail was under Hojeda, Americo was in charge of two ships with freedom to navigate and explore as he saw fit, though not against the advice of the ships’ captains. He had not yet discarded the notion of Columbus that the lands west of the Atlantic were part of Asia. The voyage was primarily for the purpose cited by Americo as his intention to see whether he could sail into the Indian Ocean (Sinus Magnus) by turning a headland that the maps of Ptolemy called the Cape of Catigara, and which they placed at 8° South. Marco Polo had sailed from China into the Indian Ocean, and Americo sought the strait through which Marco Polo had passed in 1292.
The expedition sailed from Cadiz in May, 1499. The ships remained in consort until far enough to the west to be out of reach of Portuguese interference. Hojeda then sailed west, making a landfall in the Guianas, while Americo with two ships reached the continent near the equator. There he found “two most tremendous rivers, one flowing from the west and sixteen miles wide” (one of the outlets of the Amazon) and “the other flowing from south to north and twelve miles wide” (the Para). He explored one of these rivers in small boats for over seventy miles. He then sailed between east and southeast to about 3° South, skirting the land and bucking what we know was the Equatorial Current. Defeated by the current, he sailed back to the northwest, to Trinidad and later to the islands of Bonaire and Curagao.
After a fight with the natives on the coast of Venezuela, probably in the region of La Guaira, the ships put into a harbor to enable the wounded to recover. They stayed there from August 17 to September 5, and Americo, by celestial observation, made the first practical determination of longitude in unknown and distant waters.
Hitherto, pilots had depended on dead reckoning for their longitude. They used a chip log for estimating ship speed. They had no means of knowing their local time. An hourglass works accurately only when held steady. With the motion of a ship at sea, the flow of sand may be impeded as much as four minutes in an hour.
To how many of those who have struggled through the art of celestial navigation in an era of accurate chronometers, accurate sextants, world-wide astronomical observatories and radio time signals, has it ever occurred to wonder how centuries before the invention of the ship’s chronometer, men voyaged around the world and geographers developed surprisingly accurate maps?
As early as 146 to 126 B.C., Hipparchus, the Greek astronomer on the island of Rhodes, established the geographical system of latitude and longitude. He indicated that the simplest method of determining longitude would be to observe the time of some celestial phenomenon which occurs at the same instant for the whole world, from two geographically separated points. For this purpose, he suggested lunar eclipses.
At the time of Americo’s youth, there were two leading astronomers whose teachings and/or data were available, and who knew, in theory, that lunar intervals might be used to determine longitude. The first of these was Regiomontanus (Montereggio), who published a volume, Ephemerides astronomicae, in 1474, calculated for 32 years in advance, in which the method of lunar distances for determining longitude at sea was recommended and explained. The second astronomer who influenced Americo was a Florentine scholar and banker by the name of Paolo dal Pozzo Toscanelli (1397-1482). Through some Portuguese navigators, he gave the idea of circumnavigating Africa to Prince Henry the Navigator, as well as in 1474 propounding to a Portuguese friend, Fernando Martinez, and soon after to Christopher Columbus, the more sensational idea of sailing westward toward the Indies. While there is no documentary proof of Americo’s having met Toscanelli, the belief that they were well acquainted is inescapable. Americo in Florence was educated largely by his uncle, Giorgio Antonio Vespucci, one of the leading intellectuals of the city. Giorgio Antonio had been educated by a pupil of Toscanelli. He conducted a school or the sons of noblemen in Florence and carried on a sort of scholarly salon that had been instituted by Toscanelli. Americo was intimately associated with this group and corresponded with them in later life. Thus irrespective as to whether or not he was personally a student of Toscanelli, through his interest in astronomy, cosmography, and geography, Americo was thoroughly indoctrinated in the Toscanelli heritage.
Americo’s own statement of the problem of longitude as he faced it on the coast of Venezuela on the night of August 23, 1499, and his solution of it, are in his Letter from Seville:
“As to longitude, I declare that I found so much difficulty in determining it that I was put to great pains to ascertain the east-west distance I had covered. The final result of my labors was that I found nothing better to do than to watch for and take observations at night of the conjunction of one planet with another, and especially of the conjunction of the moon with the other planets, because the moon is swifter in her course than any other planet. I compared my observations with the almanac of Giovanni de Montereggio, which was composed for the meridian of the city of Ferrara, correcting with calculations from the tables of King Alfonso.
“After I had made experiments many nights (ascertaining his local midnight by halving the time elapsed with hour and minute glasses between sunset and sunrise), one night, the 23rd of August, 1499, there was a conjunction of the moon with Mars, which according to the almanac was to occur at midnight or a half hour before. I found that when the moon rose an hour and a half after sunset, the planet had passed that position in the east. That is to say that the moon was about one degree and some minutes farther east than Mars, and at midnight her position was five-and-a-half* to the east, a little more or less.”
A modern computation made to check Americo’s observations indicates that his probable error on August 23 was 10 minutes of arc, or eighteen minutes of time, a little more than 4½° of longitude.
At his farthest west on the Second Voyage, at Cape de la Vela, he observed a conjunction of the moon with Jupiter on September 15, and probably also one with Mars on September 19. In each case, Regiomontano’s Ephemerides timed the moon late by an hour or so. Its sidereal day began with noon, and it gave “Hour 1” as the time at Ferrara of the conjunction with Jupiter, making Americo think the conjunction occurred at Ferrara after midday, whereas the actual time of its occurrence at Ferrara was nearer to 11 A.M. Americo’s error of one hour and four minutes of time, or 16° of longitude, may be entirely accounted for by Regiomontano’s error.
Americo’s method was as good as the reliability of the almanac and the accuracy of his instruments permitted. From his farthest west on the Second Voyage, he sailed to Espanola (Haiti) where he wintered. He reached Cadiz on September 8, 1500.
His studies of longitude had only begun. Back home he spent many nights making celestial observations, checking the accuracy of almanac predictions, perfecting his techniques, and gathering information as to precise times of the same conjunctions as observed in Spain and Italy, which he had observed in Venezuela and elsewhere in the West. This work, in which he “lost much sleep,” prepared him for the most remarkable determination of longitude previous to modern times, made on the third of the Four Voyages.
His estimate of longitude had convinced him that the land east of the mouths of the two tremendous rivers lay east of the Line of Demarcation and belonged to Portugal. Since he knew there was no strait through the continental land north of those rivers, the passage to India must be sought to the south of them. If he were to pursue the search, which must be along the coast of land belonging to Portugal, he knew he would have to go on a Portuguese ship. Through the solicitation of influential Florentine friends in Lisbon, Americo was summoned by King Manuel of Portugal. He was commissioned as an explorer. On May 13, 1501, he sailed from Lisbon with three caravels, going “solely to make discoveries and not to seek for any profit.”
At Cape Verde en route westward, Americo met two returning ships of Cabral which had been to India via the Cape of Good Hope. From Cape Verde, Americo wrote to his Florentine patron that from a seaman on one of these ships, he had acquired knowledge which corrected some of the Ptolemaic concepts of geography.
He made his landfall near Cape San Rocco on August 16. He explored the coast of Brazil southwestward, naming Cape Saint Augustine on August 28, and determining its latitude with repeated observations as 8° South. He was surprised not to find thereabouts what he sought; for this was the latitude of Marco Polo’s Strait of Catigara (probably in actuality Sundra Strait between Java and Sumatra). Questioning all his preconceptions, he continued his search along the coast. He entered and named the Bay of All Saints (Bahia) on November 1, and entered and named the River of January (Rio de Janeiro) on January 1. At 25° South he entered a port (the modern Cananea), which his observations for longitude convinced him was on the Line of Demarcation and therefore the last port belonging to Portugal.
We know this is so because at the entrance of the bar of Cananea on the continental side, on the top of a cliff, was erected a marker of European marble, bearing the coat-of-arms of Portugal.
Consider a moment this recognition of the longitudinal position of the Line of Demarcation. The Line of the Treaty of Tordesillas “370 leagues west of the Cape Verde Islands,” allowing 16 2/3 leagues to a degree, actually runs north-south through Cananea. The site of the boundary marker inside the mouth of the harbor of Cananea is at 22° 10' west of San Antonio, the westernmost of the Cape Verde Islands. 370 leagues at 16 2/3 leagues to a degree equals 22° 12'. In a distance of 1500 miles, Americo was correct within two minutes of longitude!
Of course, such accuracy was in a measure, accidental, but it was the kind of accident which happens to a good scientist who constantly perfects his techniques.
Portuguese jurisdiction ended at Cananea. Since further navigation along the coast extending southwestward would take the ships into waters belonging to Spain, a decision had to be made. A meeting was held ashore and the crews voted unanimously to continue the voyage. Thereupon, the Portuguese leader of the expedition, probably Gonzalo Coelho, knowing he could not legally retain responsibility in Spanish waters, resigned. Americo, the neutral Florentine, but a resident (not yet a citizen) of Spain, was chosen Commander.
Sailing southwestward, Americo remained as far off shore as possible, while surveying the coast for a passage to the west. He discovered the La Plata River, which he named the River Jordan. On February 27, he reached his southernmost port, at 49° 21' South, naming it Porto de San Giuliano. This was probably the Puerto St. Julien later visited by Magellan.
The decreasing volume of outflow and size of the rivers, indicating the narrowing of the continent, and the westward trend of the coast, had convinced Americo that he had been approaching some kind of passage to the west. On this voyage he had explored about 3,300 miles of coastline. Temperatures had been mild, seas moderate, fresh food plentiful, and the natives friendly. However, staple supplies were running short, the hulls were getting wormy, and the time for return had come. On leaving Port San Giuliano, they ran into a typical Cape Horner. Americo headed north for home, having been within 250 miles of the Straits of Magellan, and possibly having observed the Falkland Islands during the storm. They reached Lisbon on September 7, 1502.
What Americo learned on the Third Voyage was of outstanding significance. We clear the way for it by merely mentioning the Fourth Voyage (1503-4), which discovered the Fernando de Noronha Island in mid-Atlantic, and started a settlement at Bahia.
By the time Americo returned to Lisbon from the Third Voyage, he had made a sensational discovery in regard to the southern continent whose shores he had explored in two or three voyages for more than 6,000 miles. Because of its far extension southward to 50° South with no strait, and from his close-to-correct determinations of its longitudinal positions, he knew that it was not part of Asia. He knew also that it was not even near Asia. He knew that it was a hitherto unknown new continent. After Asia, Africa, and Europe, it was the Fourth Continent, or as Americo put it, “what we may rightly call a new world.”
This was the most important news that ever came to Europe. Americo stated this greatest of geographical discoveries in his Letter from Lisbon, 1502, in which he told his patron Lorenro that he had assembled all the new notable information “in a small work.” But the Portuguese king retained this work and confiscated his notes and all his written data, so that when Americo returned to Spain, he carried out of Portugal only what he held in memory or in maps smuggled out through Florentine friends. Thus Americo’s projected book never materialized, and all we have aside from his letters, is a pamphlet, Mundus Novus, published in August, 1504.
When Americo returned to Spain, he married. He was well received by King Ferdinand. He was made a citizen of Castile and Leon, given the rank of Captain, the title “Astronomer to the King of Spain,” and later was appointed to an office created for him, that of Pilot Major of Spain.
As Pilot Major, he was the official cartographer of the kingdom, and all pilots had to take instruction from him and report to him any new discoveries. He almost certainly made two short voyages to the Caribbean on commercial trips for the king. He planned a further trip below 50° South to discover a southern passage, which he had reason to believe existed, and he considered sheathing his ships with lead to withstand teredo worms. This voyage was prevented by international complications, being protested by Portugal. As Pilot Major, Americo passed on to posterity his great contribution to the art of celestial navigation.
In his Letter from Seville, 1500, he had declared the length of a league to be four miles (Roman miles). Columbus held it to be only 3½ miles, and so did the Portuguese under Cabral. All at the time agreed, Columbus, Americo, the Spanish and the Portuguese, that there were 16 2/3 leagues in a degree. But Americo’s astronomical studies showed him that 16 2/3 leagues of four Roman miles each were insufficient for an actual degree. In his Letter from Cape Verde, June, 1501, he told his Florentine patron that a league was “four and half miles” (ogni lega è quatlro miglia e mezzo). He had been compelled to enlarge his conception.
This larger measure agreed with what he knew of longitude. A degree of 16 2/3 such leagues was 75 Roman miles. This meant that Americo’s new estimate of the circumference of the earth was 27,000 Roman miles, or 24,852 English miles. Compare this with the circumference as established by modern science, which is 24,902 English miles. Americo was within fifty miles of correct!
Eratosthenes, whose terrestrial measurement in ancient times won him such a reputation that ever since people have fondly tried to credit him with a near hit, was grossly in error, since in English miles his estimate would be 28,919. Ptolemy had the earth far too small, 20,710 English miles, and Columbus, because he wanted it so, even smaller, 18,777 English miles. Toscanelli, giving him the benefit of the most favorable interpretation, was nearer to correct than anyone previous to Americo. Toscanelli may be credited with an estimate of the earth’s circumference as 25,050 English miles, or only 148 miles of error. Americo’s estimate, with only fifty miles of error, meant with allowance for Ptolemy’s exaggerated estimate of the longitudinal distance from Cadiz eastward to Catigara (about 170° according to Ptolemy), that in Americo’s mind, Cape Saint Augustine on the Brazilian elbow, which he must have estimated as less than 35 degrees west of Cadiz and which should have been the site of the Strait of Catigara if the land on the western side of the Atlantic was Asia, was more than 155 degrees or more than 10,000 miles from Catigara. With the same reliance on Ptolemy’s maps, Americo knew that his own farthest west in the New World was nearly 5000 miles from the nearest point on the eastern shore of Asia.
Since Ptolemy, Marco Polo, and all reports agreed that there was a great ocean east of Asia, and there was a hitherto unknown great continent on the western side of the Atlantic, that ocean east of Asia must be a different ocean from the Atlantic, an ocean for which Europeans did not yet have a name. Thus Americo’s was the first human mind to conceive of the New World or Western Hemisphere as great continental lands lying between the Atlantic Ocean and another possibly greater ocean not yet named. He was the first human being to en vision the principal land and water masses of the earth.
In due recognition of his contribution to geography, a geographer in Saint-Die, Lorraine, published a map of the world in 1507, naming the new southern continent America. The name was deservedly given.
Americo was too great to go without detractors. Some said he had stolen credit that belonged to Columbus. They said he falsely claimed priority in sighting the new continent. We have seen, however, that it was not priority which gave Americo the conception of a new continent. It was much more extensive exploration than Columbus did, coupled with a celestial determination of longitude by science beyond the capacity of an untrained mind.
The method of ascertaining longitude by lunar distances, first used practically by Americo Vespucio, was the only effective method navigators had for more than 250 years, until the recognition in 1765 of the invention by John Harrison of the ship’s chronometer, “good enough to determine longitude within thirty miles after six weeks at sea.” In the account of the 18th century voyages of Captain James Cook we read: “Lunar observations, in their turn, are absolutely necessary, in order to reap the greatest possible advantage from the timekeeper; since, by ascertaining the true longitude of places, they discover the error of its rate.” Captain Cook is quoted by Von Zach as follows: “The method of lunar distance from the sun or stars is the most priceless discovery which the navigator ever could have made, and must render the memory of the first discoverer of this method immortal.”
Americo Vespucio was an explorer, a cartographer, the best pilot of his day, an unraveler of other men’s confusions, a navigator who first gave the world a practical method of determining longitude. Since he was the man who proved that South America was a new fourth continent, and since he gave Europe proof that lands west of the Atlantic constituted a hitherto-undreamed-of Western Hemisphere separated from Asia by another great ocean, he fully deserved the honor of having the new continents named after him.
*Copyist’s error for three and a half.