Solving the case of the lost Maya codex
Banner image: Detail泭from a document called the Grolier Codex. (Credit: Gerardo Guti矇rrez)
Josue Sa矇nz Trevi簽o, a renowned collector of antiquities, probably didnt know what he was getting himself into when he unwrapped the little manuscript, no bigger than a cocktail napkin.
[video:https://youtu.be/8C93IGcCOXw]
The year was 1965. Sa矇nz, then president of Mexicos Olympic Committee, had just hopped on a plane and flown to a spot somewhere near the states of Chiapas or Tabasco. There, as Sa矇nz would later reveal, he met with a group of grave robbers who presented him with the booklet.
All of this was shady but, sadly, not illegal at the time, said Gerardo Guti矇rrez, a 91勛圖厙 archaeologist who studies pre-colonial peoples of the Americas.泭
It was also potentially the find of Sa矇nzs life. The document itself bore a series of paintings on bark paper depicting the passage of Venus through the night sky. They were intricate, colorful and, at least on the surface, seemed to date back hundreds of years to the height of Maya civilization. 泭
As far as scholars knew, only three such books, called Maya codices, had ever been discovered, and all of them were sitting in museums in Europe. What Sa矇nz held in his hands might be a long-lost fourth.
It could also have been a forgery.泭
More than four泭decades after that fateful plane ride, Guti矇rrez served on a scientific team that set out to answer the question once and for all. The archaeologist turned art detective uses high-tech tools to probe the secret lives of paintings, ceremonial masks and more.泭
Recently, for the Pre-Colombian Society of Washington, D.C. The archaeologist, whose career spans two decades and several continents, is using the opportunity to reflect on his most nerve-wracking case to dateone that brought him face-to-face with what may have been the oldest surviving book from the Americas.
I was worried because I was walking into a debate that had gone on for decades, and nobody was going to be happy about the results, said Guti矇rrez, an associate professor in the Department of Anthropology. It was very risky.

A section of the Grolier Codex. (Credit: Gerardo Guti矇rrez)
The detective in his lab
A couple of years later, Guti矇rrez shows off what he calls his mobile laboratory from his office on campus. It includes a wide range of portable instruments, such as ultraviolet and infrared lights and several different kinds of microscopes.泭
Top: Gerardo Guti矇rrez uses a device called an X-ray fluorescence (XRF) spectrometer to scan a mural painted on a rock shelter called泭Cauadzidziqui in the Mexican state of Guerrero; Middle: Guti矇rrez studies a portrait of a novice泭nun painted in the 1700s in Mexico; Bottom: Guti矇rrez photographs a scroll called the Codex Garc穩a Granados, which was painted much later than the Grolier Codex. (Credits: Gerardo Guti矇rrez)
He pulls out one scientific tool, a device called an X-ray fluorescence (XRF) spectrometer, that looks like a sci-fi ray gun.
Do you remember in Star Trek when they would have to identify the components of objects on different planets? he said. This does the same thing.泭
It also helps Guti矇rrez to pursue his obsession with color and, in particular, pigments.泭
The archaeologist has brought his mobile lab with him to collections from all over the world in American and Mexican museums through an effort he calls the Colors of History Project. Guti矇rrez uses these tools to examine the chemistry underlying everything from ancient cave paintings to Renaissance-era portraits.泭
His favorite pigment is called Maya Blue. Made by mixing the indigo plant with a type of clay, this molecule looks more turquoise than a deep blue. The color appears in a lot of artwork from buildings in pre-colonial Mesoamerica to Spanish colonial churches, in part because of its staying power.
Its really an immortal pigment, Guti矇rrez said. You can put anything on itstrong acids and bases. You can expose it to weathering and, more importantly, time. It wont degrade. The only thing Maya Blue cant resist is direct fire.
It was Guti矇rrezs experience with this immortal pigment that brought him face-to-face with the manuscript that Sa矇nz purchased all those decades ago.
The case of the codex
What happened in the years after Sa矇nz bought the booklet off of the grave robbers in 1965 is murky. In 1972, however, it turned up in New York where its pages were displayed on black velvet in the Grolier Club, a haunt for the citys blue bloods.泭
Known as the Grolier Codex, the book soon became caught up in the rivalry between two competing schools of Maya scholars. One claimed that the book was authentic, while the other contended that the manuscript was merely a clever forgery.
The debate lingered for decades. In 2016, a U.S.-based team claimed that it solved the mystery, but some experts considered the researchers too biased and downplayed their results.
One year later, Mexicos National Institute of Anthropology and History decided to put the question to rest for good. It assembled a dream team of scientists from several different universities in Mexicoplus Guti矇rrez and his CU mobile lab.泭
The researcher still remembers seeing the book for the first time. By that point, it was stored in the basement of the National Museum of Anthropology in Mexico City in a vault Guti矇rrez compares to Fort Knox. He was blown away by the sheer detail of the paintings. One illustration depicted a being who scholars call the Death God wearing a jaguar headdress. Another showed a second god with the legs of an eagle.泭
It was just amazing seeing it, he said. But as a scientist, I had to hold my feelings in.
Guti矇rrez and his colleagues probed the document using his XRF machine, microscopes and more. But the silver bullet came down to Maya Blue. Using X-ray fluorescence spectrometry and other tools, the team found the pigment hiding in an illustration of water.泭
That was significant, Guti矇rrez said, because at the time when Sa矇nz met with his grave robbers, not a single person knew how to recreate the pigment.泭
I knew we had it, Guti矇rrez said. But it wasnt until one of the other teams sent me a photograph by email of a scanning electron microscope image that clearly showed Maya Blue when I said, Yes, thats it.
The book, in other words, was undeniably a fourth Maya codex. Other analyses suggested that the manuscript dated back to the 11th or 12th centuries, a timeline that made it the oldest known American book. It also remains the only codex that resides in Mexico.泭
With the mystery solved, Guti矇rrez is planning his next high-profile case. Hes examining whether there might be two different recipes for making Maya Blueone pioneered by Maya around 300 AD, and another by the Mixtecs and Aztecs much later in 1300 AD.泭
For now, Guti矇rrez is satisfied that the fourth Maya codex, still in its vault, will finally get some peace.泭
Its time to stop using it as a lab rat where every year another team comes and takes pieces of it, he said. We have to begin to treat this document with the respect it deserves.
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