The Portuguese Foundation of New World Cartography

by Gunnar Thompson

Since the beginning of Atlantic maritime history, the Portuguese claimed that their ancestors reached the New World ahead of Spain’s champion--Christopher Columbus.  Now, a recently re-discovered Portuguese map from 1436 confirms this claim.  Hidden away in Chicago’s Newberry Library for over 30 years, the Atlantic portolan chart by Andrea Bianco clearly shows the peninsula of Florida almost a century before it was officially named by Ponce de Leon. 

Although Bianco’s chart served as the foundation for the earliest maps of America, it was not available to Columbus.  Other maps drawn from the Portuguese arsenal of commercial espionage led the Spanish mariner to his encounter with destiny in the Caribbean Sea.  These “public maps,” by such renowned cartographers as Henricus Martellus and Martin Behaim, showed the Zaiton Peninsula and Japan (actually Florida and the Antilles) as part of Asia.  This region was the objective of Columbus in 1492.  He actually reached that objective without realizing that the isles he found were not part of Asia.  Meanwhile, Bianco’s chart remained hidden among the secret documents of the royal cosmographer.  It was not until 1502 that a spy for the powerful Italian Este Family obtained a copy of the secret Portuguese map of the New World.  This map, the so-called “Cantino map,” and all subsequent maps of the New World in the Lusitano-Germanic tradition trace their origins back to Bianco’s portrayal of a new island continent in the Atlantic Ocean

The Mystery of Antillia

Even before Portugal’s Prince Henry The Navigator popularized maritime exploration in the early 15th century, there were legends of ancient voyages across the western sea.  During the reign of King Solomon (974-937 BC), the western isles were known to Iberian merchants by such names as “Colchis,” “Asqua Samal,” and “Bracir.”  In the 1st century AD, the Sicilian geographer Didorus Siculus recounted tales of a Phoenician paradise that was located in the far-western Atlantic Ocean.  This “paradise” served as a refuge for seven Portuguese bishops during the 8th-century Saracen invasion of Portugal.  According to a legend recorded on the Johannes Ruysch map of 1508, the bishops fled along with their parishioners and assorted farm animals to the western isle.  The name given to this overseas refuge was “Antillia” or “the Isle of Seven Cities.” 

Most 15th-century Portuguese charts of the Atlantic Ocean include two stylized rectangles representing the legendary western isles.  Usually, the southern-most isle is called “Antillia;” while the northern isle is some variation of “Satanaxio” or “Saluaga.”  The name “Antillia” has been translated as “isle before the mainland” or “the island opposite Tile” (where Tile represents the Roman Arctic frontier of Iceland).  Figure 1 shows the earliest known Portuguese version of the Western Atlantic seen on a 1424 chart most commonly known as the “Pizzigano Portolan.”  On this map, Antillia is situated in the far west at the latitude of the Strait of Gibraltar.  However, this map is not the earliest example of western isles in that locality.  Two Arabic maps (Figure 2), by Al-Idrisi in 1154 and by Ibn Said ca. 1250, reveal that legends or actual reports of overseas isles were common knowledge among cartographers at an early date. 

When Portugal’s Prince Henry The Navigator inaugurated his campaign to explore the Atlantic Ocean in 1418, finding the lost isles of Antillia and Seven Cities was a major concern.  Royal charters issued to eager explorers during Henry’s lifetime and even up to the time of Columbus clearly stipulate “Antillia or the Isle of Seven Cities” as the principal objective.  Even Bristol merchants sought after Antillia along with another illusive isle in the west--Hybresail. 

In addition to sending vessels to explore the west coast of Africa, Henry dispatched Goncalo Velho Cabral to look for Antillia or the Isle of Seven Cities in 1425.  Although Captain Cabral’s first mission has been characterized as a failure due to the lack of any published report of success, he apparently located the Azores in 1427.  This occurred during another effort to find the lost western isles.  Vague reports of isles that were sighted farther west and to the north occasionally found their way into the correspondence of Portuguese mariners; however, official chronicles remained silent regarding the outcome of such expeditions due to the policy of secrecy imposed on royal ventures.  Diogo de Sevill sailed west in 1427.  Goncalo Cabral sailed west again in 1431.  According to Ferdinand Colon, the son of Columbus, a Portuguese vessel had reached Antillia by this point in time.  It was a notable event in the folklore of the dockyards and quays of Iberia because the crew of one Portuguese vessel reported finding gold in sand taken from the shore.  Joao Fernandes (the laborador for whom Labrador is named) sailed repeatedly between 1431 and 1486.  Vincent Dias sailed west in 1445; Diego de Tieve’s commission in 1454 stipulated that he seek the Isle of Antillia.  According to Pedro Velasco, a confidant of Columbus, the isle of Antillia had been sighted prior to Diego’s mission.  Numerous western expeditions followed: Dom Fernao in 1457; Joao Vogado in 1462; Jao Vaz Corte-Real in 1464; Ruy Concalves da Camera in 1473; Fernao Telles in 1474; Antonio Leme and the daFonte brothers in 1476; Fernao Domingo de Arco in 1484; Fernao Dulmo, Alfonso de Estreito and Martin Behaim in 1486; and three more expeditions by Vincent Dias between 1482 and 1494. 

The Dulmo-Estreito expedition must have been a success of some consequence because Ferdinand Colon reported that they had reached the “Isle of Baccalaos” (a.k.a., the isle of stockfish or cod).  This was an early Portuguese-Bosque name for Newfoundland and the Grand Banks.  Another Portuguese name for the same region was “Corte-realis”--in honor of the explorer Jao Vas Corte-Real and his sons. 

Transformation of a Legendary Isle into a New World

Cartographic evidence offers the most convincing proof of the success of early Portuguese voyages across the Atlantic.  The Andrea Bianco map of 1436 (Figure 3), portrays a totally new version of the legendary Antillia.  This Antillia includes a southeastern peninsula attached to the usual, rectangular isle that is most commonly seen in Portuguese Atlantic charts.  The peninsula has an unmistakable hook-shape appearance that is characteristic of Florida.  Bianco’s Antillia is situated directly across from Europe at the latitude of the Strait of Gibraltar (Figure 4 and 5).  Skeptics might argue that this is the wrong latitude and longitude for Florida--which appears too close to Europe in the middle of the ocean and too high on the globe at 34˚N.  Indeed, Florida lies some 4,000 miles to the west, and its southern tip is closer to 25˚N.  If we keep in mind that determination of geographic coordinates was not a precise science in 1436, and if we realize that the placement of the southeastern peninsula on this map is consistent with the location of Florida on early 16th-century maps, then we must realize that representation of Florida is a distinct possibility. 

An even greater issue for scholars of American history is that Bianco’s characterization of the New World seems to have served as the genesis for later maps of North America.  Indeed, there is a direct connection between the cartography of Bianco and the great cosmographers of the Americas including Amerigo Vespucci, Martin Waldseemuller, and Gerhard Kramer (a.k.a., Mercator).  A comparison of Bianco’s “Antillia” from the 1436 map with isles called “the Antillias” on the Alberto Cantino map of 1502 (Figure 6) reveals a continuation of the earlier concept of a large isle or mainland with a peculiar southeastern peninsula that is separate from Asia.  The Cantino map portrays a rectangular island with a hook-shaped peninsula facing to the southeast at the latitude of the Strait of Gibraltar.  This peninsula features bays, promontories, and rivers in such great detail as to suggest a fairly extensive survey of the region (Figure 7).  What is new on the Cantino map is the enlarged size of Antillia relative to Europe and its placement about 4,000 miles to the west.  This is a fairly accurate estimate of the distance from Florida to the Old World.  Of course, the latitude is about 10˚ too far north on the Cantino map—just as it was on Bianco’s chart. 

The identity of Antillia as an early representation of the Florida region is confirmed by its proximity with Cuba and Haiti (which bear the titles Isabella and Spagnola on the Cantino map).  Directly below these isles lies the emerging coastline of a southern continent--an “unknown land” or terra incognita which Amerigo Vespucci was to characterize as a “New World.”  Since Florida was not “officially” discovered until the Ponce de Leon expedition of 1513, map historians have argued over the true identity of this precocious peninsula of Antillia.  Kenneth Nebenzahl called it “the greatest unsolved cartographic puzzle of the period.” 

Puzzled historians have wondered: “Who could have made such a map?”  Nebenzahl offered as suggestions either Vespucci or some unknown Portuguese pilot.  Vespucci is certainly a contender due to his extended voyage north from Parias (Costa Rica) in 1497 and his service as a Portuguese navigator in 1502.  The British writer, Ian Wilson, has postulated that John Cabot sailed along the East Coast from the New England region to the Caribbean Sea in 1498.  There is some support for Wilson’s interpretation since Cabot’s charts apparently found their way into a map by the Spanish adventurer Juan de la Cosa.  And this map shows a northeastward tending mainland for the first time adjacent to the Antilles.  This northeastward tending coastline is a gross distortion of the East Coast caused by the excessive degree of magnetic declination encountered between Florida and Greenland.  Similar coastal distortions are seen in subsequent maps of the region by Sebastian Cabot, Hieronimus Verrazano, and Vesconte de Maggiolo.  The 16th-century historian Peter Martyr suggested another candidate: John Cabot’s son, Sebastian.  According to Martyr, the wayward son claimed that he had sailed along the Florida coast past Cuba

Another historical figure who might have played a role in mapping Florida before it was “officially discovered” by Ponce de Leon was the English Franciscan, Nicholas of Lynn.  Both Ferdinand Colon and another Columbus biographer, Bartolomew de Las Casas, credited an anonymous English Franciscan with writing about certain isles west of Europe in a 14th-century book called Inventio Fortunatae.  English historian Richard Hakluyt identified the author of that book as Nicholas of Lynn--a Franciscan who was skilled in using the astrolabe. 

Regardless of who was responsible for early mapping expeditions to the shores of Florida, the Cantino version of the Western Atlantic served as the basis for a geographical construct--a New World mainland--that eventually became North and South America.  Either this map or similar copies of the secret original version inspired the “Lusitano-Germanic” tradition of cartography.  Over the course of four decades, Portuguese and German cartographers continued to elaborate upon the concept of a “New World” comprising mainland and isles that were separate from Asia and situated about 4,000 miles to the west.  Maps by Nicolo Caveri (1504) and Martin Waldseemuller (1507) document the progressive transformation of Antillia into a New World continent (Figure 8).  In the Caveri map, we see the region west of the Florida peninsula evolving into the Gulf of Mexico, while the continent to the south continues to grow towards the west along the southern shores of the Caribbean Sea.  This is precisely the kind of gradual cartographic improvements we would expect to see as field reports from navigators, explorers, and colonists, made their way back to the headquarters of the chief cosmographers in Portugal and Germany

In the 1507 map by Martin Waldseemuller, we see Antillia enlarged into a mini-continent with mountains.  This northern mainland, known only as “terra incognita,” is only separated from the southern continent by a narrow isthmus.  By this point in time, Waldseemuller had decided to honor Amerigo Vespucci for proving that the southern continent was a “New World” that was totally separate from Asia.  In a 1502 letter to Lorenzo DeMedici, Vespucci reported sailing along the coast of the new continent from “eight degrees above the Equinotical line towards the Antarctic pole.”  He wrote about the primitive inhabitants of the Brazilian jungle, and he enumerated new species of animals that were unlike any found in the Old World.  He ventured his opinion that so many new kinds of animals could not possibly have fit into Noah’s Arc--thus he announced his heretical departure from doctrinaire beliefs and biblical geography.  He also devised a new method of using the nocturnal convergence of planets with the moon to provide a much more accurate means of estimating longitude; and he accurately determined the circumference of earth--thereby providing a scientific basis for proving the insular nature of the southern continent.  It was in recognition of this enormous breakthrough in scientific thinking and the brilliant departure from archaic paradigms that Waldseemuller decided to honor Vespucci by naming the southern continent in his honor (Figure 9).  Thus, Waldseemuller’s map is the first to bear the name “America” across the southern continent. 

The name “America” had a tenuous existence during the early years of New World cartography.  Such titles as “Terra Nova,” “New India,” “Brazil,” and “India of the West” were common alternatives found on maps of the era.  Those cartographers who were loyal to Church doctrine, the so-called “biblical geographers,” attempted to perpetuate the fiction that the new lands to the west were part of Asia (or “the Indies”).  Their maps showed the New World lands connected to Asia by way of a gigantic mega-continent that spanned the globe from China to Florida or New England.  The name “America” was even erased from subsequent editions of maps by Waldseemuller and his associates who were forced to recant their earlier support for the heretic Vespucci. 

Meanwhile, cartographers in the Lusitano-Germanic tradition expanded upon Waldseemuller’s model of a totally separate New World.  In the Vesconte de Maggiolo map of 1527 (Figure 10), we see the impact of new information from the most recent explorations by Giovanni Verrazano in 1524.  He charted the entire East Coast from the Carolinas to Newfoundland.  Maggiolo added this extended coastline to the existing base of Antillia, which by then was known simply as the “Territory of Florida.”  Verrazano reported a huge sea beyond the outer banks of Pamlico Sound north of Florida which provided a convenient barrier between the new lands he claimed for France and Spanish colony to the south.  Maggiolo’s map includes the fictitious isthmus between the northern and southern mainlands that was also seen on Waldseemuller’s map. 

When the Flemish cartographer Mercator published his world map in 1541 (or 1538), the name “America” appeared for the first time on both the northern and southern continents.  This map (Figure 11) represents the epitome of the Lusitano-Germanic tradition, and it served as the model for most subsequent maps of the Americas.  Mercator’s map not only shows the northern continent with its various regions all fused together, it shows the tip of Florida at the correct latitude with the Antilles (Cuba and Haiti) situated below the Tropic of Cancer. 

Mercator’s decision to honor Amerigo Vespucci was probably rooted in his own experience as an arrested heretic and his conviction that Vespucci had effectively proven the insularity of the New World from Asia.  As one of the most skilled and innovative mapmakers of his age, Mercator had the good fortune of becoming a favorite artist during the rising tide of the German publishing industry.  Skill and good fortune guaranteed success for Mercator; and his fame assured the eventual popularity of the name “America” for both continents of the New World

Two Concepts of Florida

A search for antecedents to Florida on the Bianco map of 1436 turned up some surprising results.  The Albertin DeVirga map of 1414 has a continent reaching out from the northwestern side of Norway (Figure 12).  At the tip of this continent, above what is called the “Caspian Sea,” is a hook-shaped peninsula that is similar to Florida in general configuration and proximity to a gulf with large islands.  On this map, the Caspian Sea is most likely an early Roman name for the Gulf of Mexico.  As this northwestern continent is characterized as a province of Norway--which follows King Haakon’s declaration of sovereignty over lands to the northwest in 1261--the most likely surveyor of historic renown is the English Franciscan Nicholas of Lynn.  The friar is known to have conducted rather extensive explorations in Nordic provinces to the west as recounted in the lost book, Inventio Fortunatae (ca. 1360).  This hook-shaped version of the Atlantic peninsula shows up again on the Henricus Martellus Germanus maps of 1489 and 1490.  Earlier antecedents showing the macro-peninsula attached to mainland Asia (or India) include a 5th-century Roman map by Macrobius and a 14th-century map by Marino Sanudo (Figure 13). 

The principle issue for early Renaissance cartographers seems to have been whether the Florida peninsula was part of Asia (which the ancients referred to as “India”) or whether it was connected to a separate isle called Antillia.  Most maps portray the macro-peninsula attached to a western mainland (Figure 14).  This is the case with respect to the Yale Vinland map (c. 1440), a Florentine Portolan of 1447, the Genoese map of 1457 (sometimes attributed to Paolo Toscanelli), a map by Fra Mauro (1459), and maps by Martellus (1489 & 1490) and Behaim (1492) just prior to the Columbus voyage. 

The Columbus Misconception

The maps by Martellus and Behaim are of particular interest as they were sponsored by the Portuguese, and they portray the Atlantic Ocean in a manner that is virtually identical to the geographical concepts of Columbus.  These maps presume an Earth circumference of about 18,000 miles--or roughly one-fourth too small; they show Florida as a peninsula of Asia called “Zaiton” or “Mangi” that is situated roughly 4,000 miles west of Europe on the Tropic of Cancer, and they have a huge isle to the east about 1000 to 1500 miles from the mainland.  This placement of the huge isle was in accord with Marco Polo’s Travels--which told of a golden isle called Cipangu (Japan) that was 1500 miles east of China.  This region was the prime target of Columbus in 1492.  He sailed along the Tropic of Cancer for about 3,000 miles with the expectation of finding land. 

As we have seen from the many expeditions that Prince Henry sent to the west in search of Antillia and the gradual improvements in Portuguese cartography regarding the actual location of the Zaiton peninsula (Florida), the accuracy of Portuguese charts with respect to the position of mainland and isles in the Western Atlantic was not at all coincidental.  Figure 15 presents a comparison of the relative locations of the Western Atlantic macro-peninsula according to 15th-century cartographers.  By 1490, the Zaiton Peninsula was thought to be situated within a few hundred miles of the actual location of Florida with Antilia (a.k.a., Japan or Ophir) situated about 1,500 miles due east on the Tropic of Cancer. 

Columbus was sufficiently familiar with the official version of Portuguese geography (having served as a cartographer in Lisbon) to believe in its veracity.  And this was his tragic flaw.  He had sailed with Portuguese expeditions to the north and south; he had studied the writings of Pierre D’Ailly and the Roman scholars; but he was never able to discover the secret of Portuguese kings that the land across the ocean was a new continent.  By the time of Columbus, all Portuguese efforts to reach China and the Spice Isles were directed towards the east around the cape of South Africa--even though public maps by Martellus and Behaim clearly demonstrated that the shortest route lay due west from the Canary Isles.

Thus, Columbus proposed an “Enterprise of The Indies” as a commercial and evangelical mission to Japan and then on to mainland Asia.  His conceptualization of the Atlantic Ocean mirrored what he had seen from the likes of Martellus and Behaim in Lisbon (Figure 16).  It was due to the Spanish mariner’s belief in the accuracy of his maps that he had faith in the success of his enterprise; and the fact that he found land in 1492 precisely where he expected to it to be confirmed his belief that he had indeed reached his objective along the coast of Asia.  After the Admiral’s death, his supporters sought to establish the truth of his misconception by contriving maps showing Florida attached to Asia and by naming the new mainland “New India” in an effort to add credence to biblical geography. 

In the end, the name “America” endured on maps not because of some accident of history or some fraud perpetrated by vainglorious rivals; it endured because Amerigo Vespucci was a champion of independence in an era that demanded new ideas and new visions of the world.  And it endured because Bianco and Vespucci had been right all along: the New World was separate from the Old. 

The Author

Gunnar Thompson is the director of the New World Discovery Institute in Port Townsend.  Trained as both a psychologist and an anthropologist at the University of Wisconsin, he has continued to pursue both fields while teaching at Drake University, California State University-Fresno, and the University of Hawaii-Manoa.  He has studied ancient voyages to the Americas for the past twenty years. 

Further Reading

THE FRIAR’S MAP OF ANCIENT AMERICA--1360 AD.  Gunnar Thompson.  Radio Bookstore Press, 1996. 

LEGENDARY ISLANDS OF THE ATLANTIC.  William Babcock, American Geographical Society, 1922.


ATLAS OF COLUMBUS AND THE GREAT DISCOVERIES.  Kenneth Nebenzahl.  Rand McNally, 1990.