Waldseemueller: How Did He Know What He Knew?

I am fascinated by the subject of ancient maps. A few very old maps have proven to be quite accurate according to modern-day measurements and techniques. How did those map mapers of the Renaissance know what they knew? Did early explorers record much more accurate details then we give them credit for? Were much older maps - that no longer exist - copied, even though not accurately understood at the time? If so, who made these older maps - and when? The above isn't the best image of the Waldseemueller Map, but I like it because it it shaped in such a way to show that it should fit over a globe. Compare The Waldseemueller Map to the controversial map said to have been compiled during the voyages of General Zheng He of China dated to 1418. Gavin Menzies wrote an equally controversial book a few years ago about the General's voyages that took him around the world before any of the known European navigators made the trip. Of course, there are always the Phoenicians... The Waldseemueller Map of the world is now owned by the United States of America and is ensconced in the Library of Congress in Washington, D.C. Here is the story from The Washington Post: 16th-Century Mapmaker's Intriguing Knowledge By David Brown Washington Post Staff Writer Monday, November 17, 2008; Page A07 How was it that a German priest writing in Latin and living in a French city far from the coast became the first person to tell the world that a vast ocean lay to the west of the American continents? That is one of the bigger mysteries in the history of the Renaissance. But it is not the only one involving Martin Waldseemueller, a map-making cleric whose own story is sufficiently obscure that his birth and death dates aren't known for certain. Waldseemueller appears to have also known something about the contours of South America's west coast years before Vasco Núñez de Balboa crossed the Isthmus of Panama and Ferdinand Magellan sailed around the bottom of the continent. History books record them as the first Europeans to bring back knowledge of the Pacific Ocean. The evidence of this knowledge is in Waldseemueller's world map of 1507, perhaps the most valuable of the 5 million maps owned by the Library of Congress. It was acquired for $10 million in 2003 and went on permanent display last year. The map -- in near-perfect condition and with no other known copies -- is the oldest document that applies the label "America" to the land mass between Africa and Asia. This was, of course, in honor of Amerigo Vespucci, a Florentine navigator who had sailed to the New World for the Portuguese. (His first name was Latinized to "Americus" and then feminized to "America.") The act of naming was apparently Waldseemueller's alone; there is no evidence that the term was in use at the time. New research by John W. Hessler of the Library of Congress has made the mystery of Waldseemueller's knowledge deeper and richer. But it hasn't answered the biggest question: How did he know? "There is some probability that Waldseemueller knew something that is no longer extant -- information that we don't have," Hessler said. The researcher, 48, brings a diverse set of skills to the task. He took Latin all through parochial school and college (at Villanova University) and reads the language fluently. He is an engineer by training and is equally fluent in the mathematics of cartography. In a new book called "The Naming of America," Hessler provides the first published translation of the map's text blocks. He has also done a modern translation of Waldseemueller's book, "Cosmographiae Introductio," printed in 1507 in St. Die, France, where the cartographer was canon of the cathedral. Although Waldseemueller gets most of the credit for the map and the book, he had a collaborator, an Alsatian named Matthias Ringmann, who died in 1511. In the largest block of text on the map, Waldseemueller writes that many things remained unknown to the ancients "in no slight degree; for instance, in the west, America, named after its discoverer, which is now known to be a fourth part of the world." In "Cosmographiae," he uses similar language: "The earth is now known to be divided into four parts. The first three parts are continents, but the fourth part is an island, because it has been found to be surrounded on all sides by sea." Hessler said he thinks the phrases "now known" and "has been found to be" are crucial. They suggest geographical knowledge that is confirmed and believed, at least in some circles. "The idea that this was a total guess is far-fetched," he said. The people who knew were most likely Portuguese explorers (or at least sailed under the Portuguese flag). It was valuable, and most likely secret, knowledge. How it got to a priest-cartographer working under the patronage of the duke of Lorraine is a good question. Equally intriguing is the shape of South America. Inscribed along the western edge of that land mass in the 1507 map are the words "terra ultra incognita" -- land most unknown. But the border is not drawn as one long, ignorantly straight line. Instead, it is a series of straight lines meeting at shallow angles, implying a mixture of knowledge and uncertainty. Using a technique called "polynomial warping," Hessler re-projected the image and compared Waldseemueller's continent with the real one. There are many differences, of course. But the correlation is about 75 percent, and at two important places -- near the equator and near the place in northern Chile where the coast veers sharply to the northwest -- the width of Waldseemueller's South America and the actual one are almost the same. Things were perhaps not as ultra incognita as he let on. That is not the end of the strangeness, however. In the large text block on the map, Waldseemueller requests "that those who are inexperienced and unacquainted with cosmography shall not condemn all this before they have learned what will surely be clearer to them later on, when they have come to understand it." It is a plea. He knows his map is asking a lot. In 1516, Waldseemueller published his second great map, called the Carta Marina. It shows South America no longer as an island. The continent disappears off the left of the page, implying it is attached to Asia, which is on the right edge. Hessler has provided the first English translations of the second map's text blocks. In one of them, Waldseemueller says: "We will seem to you reader, to have diligently presented and shown a representation of the world previously, which was filled with error, wonder and confusion. . . . Our previous representation pleased very few people, as we have lately come to understand." Was this a retraction? It sounds like it. Was a continental America heresy? Hessler said he has found no reason to think it was. So why would Waldseemueller change his new view of the world to an older one? That's just one more mystery of the mysterious map.