Fifty-four years after it was sold by looters, an ancient Maya pictographic text has been judged authentic by scholars. 

Doubts over whether the document –   the oldest surviving pre-Hispanic document in the Americas  – was kosher have circulated for decades because its design and style differs from that of other surviving scripts.

The document features pictures and symbols about the planet Venus. 

But on Thursday, experts from Mexico's National Institute of History and Anthropology (NIHA) declared it the real thing following a series of tests.  

“The Mayan Codex is authentic and the oldest, legible pre-Hispanic manuscript in the Americas,” said Diego Prieto Hernández, an anthropologist and head of the Mexican institute.

The text is distinct because of its simpler design, in comparison to other Mayan artifacts  Credit: INAH/AP

The Mayan Codex, which was previously known as the Grolier Codex, was created sometime between the years 1021 and 1154 A.D. It initially came to light as a result of a looting, which is why there is no existing record about the context in which it was discovered, explained Hernández.

It was first sold to a Mexican collector in 1964, and then exhibited at the Grolier Club in New York in 1971. Josue Saenz, an antique collector, gave the text to the Mexican authorities in 1974 so that they could investigate its authenticity.

Sofia Martinez del Campo told a press conference in Mexico City on Thursday that differences in the style of the text to other surviving documents were explained by the context of the era in which it was produced. When the Mayan Codex was created, communities were more impoverished than in later times.

"The austerity of the work is explained by its epoch, when things are scarce one uses what one has at hand," said Martinez del Campo.

It was a difficult task establishing the authenticity of the text – which is printed on tree-bark – because there are no other surviving documents from that moment in time to compare it to, the experts explained.

Most texts were destroyed during the 16th Century under the supervision of Diego de Landa, a Spanish Bishop who was sent to convert the Mayan people to Catholicism after the Spanish conquered Mexico. He waged a campaign against idolatry, and ordered Mayan manuscripts burned.

Collector Josue Saenz returned the book to Mexican authorities in 1974.

The fact that it was looted and had a simpler design than other surviving texts had led some to doubt its authenticity.

"Its style differs from other Maya codex that are known and proven authentic," the institute said in a statement. About three other later Maya "books" survived an attempt by Spanish conquerors to destroy Mayan artifacts in the 1500s.

But the institute said Thursday that because the book was written so early, it had been created in an era of relative poverty compared to the other works. It said a series of chemical tests proved the authenticity of the pages and the pre-Hispanic inks used to write it.

While previous studies had supported the authenticity of the text, it was the end of decades of doubts for the book.

"For a long time, critics of the codex said the style wasn't Mayan and that it was 'the ugliest' of them in terms of figures and color," said institute researcher Sofia Martinez del Campo. "But the austerity of the work is explained by its epoch, when things are scarce one uses what one has at hand."