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Advanced Imaging Reveals Secrets of 1491 Map Columbus May Have Used

A map from 1491 that may have been consulted by Christopher Columbus is proving to be a historical treasure trove.

A map from 1491 that Christopher Columbus may have consulted is proving to be a historical treasure trove. The map, created by German cartographer Henricus Martellus toward the end of the 15th century and now housed at Yale, has faded and blurred over time, but researchers have managed to pry out its secrets with a technique called multispectral imaging.

The Martellus map as it appears to the naked eye (top) and through multispectral imaging (bottom).Yale University / Rochester Institute of Technology

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By photographing the map illuminated by a series of specific bandwidths of light and then comparing and overlapping the results, hidden details emerged that have cartographers reeling. There are descriptions of unknown peoples (clearly fanciful, but still interesting), a greater extent of Africa mapped than expected from the period, and details of Japan that suggest that Columbus likely consulted this map or one like it when preparing for his famous transatlantic voyage.

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About 80 percent of the text obscured by fading has been recovered, according to the Rochester Institute of Technology's Roger Easton, one of the researchers. "We’re still finding things," he said in a news release. "One day last week we pulled out 11 characters. The next day, we got several words."

When the project is deemed complete, the maps will be made available via the website of Yale's Beinecke Library.