Lessons Learned from a Medieval Map

Minutes

President Joseph Coates, called the 2066th meeting to order at 8:21 p.m. on December 13, 1996. The Recording Secretary read the minutes of the 2065th meeting and they were approved. The President announced the annual General Business Meeting to follow the regular meeting.

Mr. Coates then introduced Ms. Jacqueline S. Olin of the Smithsonian Institution to discuss “Lessons from a Medieval Map: The Vinland Map.”

The Vinland Map has been the subject of controversy since it first came to general notice in 1957 when it was put up for public sale. The map shows what closely resembles the northeast coast of North America depicted as an island named Vinland. A legend in the left corner describes Vinland's discovery by “Leif and Bjarni in company”. The map is drawn in ink on parchment. When the map appeared for sale it was bound with a document known as the “Tartar Relation” describing the travels of John Carpini in 1245-1247 from Lyons to Karakorum the capital of the Mongolian Empire. There were worm holes in both the map and the “Tartar Relation” but they did not align. It was later realized that these texts were similar to a third document that had been known for some time, the “Speculum Historiale” or The Mirror of History, a chronicle written by Friar Vincent of Beauvais in the mid-thirteenth century. When the “Speculum” was compared with the other two documents it was obvious that the three had at one time been bound together. The worm holes at the front of the “Speculum” match those of the map, and the holes at the back match those of the “Relation”.

In 1965 the book The Vinland Map and the Tartar Relation [1] presented evidence that the map had been drawn about 1440 and thus would have predated the voyages of Columbus by about fifty years. The “Relation” and the “Speculum” were both written on a combination of parchment and paper pages. The watermarks on the paper from each text match and correspond to paper manufactured at Basel, or two other locations, in about 1440. Paleography of the script used in the map and the texts place them all in the early 15th century and most probably by the same scribe. The map itself is a world map similar in style and depiction of Europe and Asia to maps produced by the Venetian Andrea Bianco in his manuscript atlas of 1436. On the reverse side of the map is a legend which apparently refers to the “Speculum”. It has been conjectured that the two texts were copied and the map produced to illustrate the “Speculum” during the Council of Basel, 1431-1443, when the Catholic Church was formulating its relationships with the Orthodox and Eastern churches. The provenance of the map and texts cannot be traced with certainty, but it is especially interesting that sales catalogs list a text similar to this associated with possessions of the family of Christopher Columbus.

In 1967 the map was examined at the British Museum. It was observed that the ink of the map apparently differed from the ink of the two texts. In 1968 the map was submitted for analysis by Walter McCrone Associates who reported in 1974 that the ink contained the mineral anatase, a form of titanium dioxide not used as a pigment before the 1920's [2]. The problem was studied again in 1987 by a group at the University of California at Davis using Proton-Induced X-ray Emission (PIXE) [3]. They reported finding orders of magnitude less titanium than expected in the ink, essentially the same as the background of titanium in the parchment. The McCrone laboratory countered that the anatase occured inhomogenously dispersed in the ink, and that it appeared micrographically to be well-crystallized by high temperature calcination and milled to a uniform particle size, strongly suggestive of modern manufacture [4]. The speaker pointed out that some chemical processes used for the preparation of green vitriol (ferric sulfate) from the mineral ilmenite (ferrous titanate) may lead to the precipitation of titanium dioxide crystals. Further, since green vitriol was commonly combined to make brown pigment for inks like those used in the Vinland map and other authenticated documents of the period, it might be expected that titanium dioxide would still be found in the amounts that are observed. The crystalline form and size of the titanium dioxide particles in the ink need further study, and consideration must be given to the medieval processes for manufacturing pigments if the charge of forgery based on the evidence of the ink is to be accepted.

[1] R. A. Skelton, T. E. Marston and G. D. Painter The Vinland Map and the Tartar Relation, Yale University Press, New Haven, CT, 1965.
[2] W. C. McCrone, Anal. Chem. 60, 1009-1018, 1988.
[3] T. A. Cahill, et al. Anal. Chem. 59, 829-833, 1987.
[4] K. M. Towe, Acc. Chem. Res. 23, 84-87, 1990.


Ms. Olin kindly answered questions from the audience. Mr. Coates thanked the speaker on behalf of the Society, stated the parking policy, announced the speaker for the next meeting and adjourned the 2066th meeting to the Annual Business meeting at 9:31 p.m.

Attendance: 99
Temperature: 6.3°C
Weather: raining

Respectfully submitted,

John S. Garavelli
Recording Secretary