Once, the Aztec capital Tenochtitlan had a library full of thousands of written works. But when Spanish conquistadors arrived, they destroyed almost all of these codices—long scrolls folded into books—hoping to sever local customs and history to make the conversion to Christianity easier. Now, fewer than 20 pre-Columbian documents remain.
But high-tech scanning recently boosted that number by one, Maev Kennedy at The Guardian reports. Researchers at Oxford University used the technique of hyperspectral imaging to look at one of the existing codices. Beneath a layer of plaster and chalk on the back of the later codex, they found a series of figures laid out like a cartoon strip, similar to Mixtec manuscripts found in the area of present-day Oaxaca, Mexico. Researcher detail the find in the Journal of Archaeological Science: Reports.
The new images were found in the Codex Selden, also known as the Codex Añute, which Oxford’s Bodleian Libraries acquired from collector John Selden in the 17th century. The 16-foot long codex is made of deer hide, covered in a white gesso paint, which was folded like an accordion into a book. In the 1950s, some researchers scraped off a bit of the paint revealing some colorful images below. But they did not want to damage the priceless manuscript and X-ray technology was not able to detect the organic pigments below, Mindy Weisberger at LiveScience reports.
Recent advances in technology convinced researchers to try again. The sensitive hyperspectral imaging picked up images made using red, orange and yellow ink. In total, the researchers examined seven pages of the codex, identifying 27 human figures on a single page, Weisberger reports. Some figures are wearing head dresses and carry sticks or spears. There are also glyphs that represented rivers.
“After four or five years of trying different techniques, we’ve been able to reveal an abundance of images without damaging this extremely vulnerable item. We can confirm that Codex Selden is indeed a palimpsest,” one of the study researchers Ludo Snijders from Leiden University, says in a press release. “What’s interesting is that the text we’ve found doesn’t match that of other early Mixtec manuscripts. The genealogy we see appears to be unique, which means it may prove invaluable for the interpretation of archaeological remains from southern Mexico.”
The researchers hope to scan the rest of the codex to reveal more of the Mixtec document. This isn't the first time hyperspectral imaging has uncovered buried history—the technique has examined the Gough Map, the earliest map of Britain to reveal hidden elements and bits that had flaked away, not to mention unearthed an image of a devil erased from an Armenian gospel.