Archaeologists working in a buried Mayan pyramid in Guatemala have discovered an enormous inscribed frieze richly decorated with images of gods and rulers, the Guatemalan government announced.

Dating to the 6th century, the carving has been hailed by local authorities as “the most spectacular frieze seen to date” and one of the best-preserved pieces of Mayan art ever discovered.

It was found at the pre-Columbian archaeological site of Holmul, in the northern province of Peten, by Guatemalan archaeologist Francisco Estrada-Belli below a 65-foot-high pyramid which was built over it in the 8th century.

Measuring 26 feet by nearly 7 feet, the 1,400-year-old carvings decorated the outside of a mysterious multi-roomed rectangular building. Found when Estrada-Belli and his team excavated a tunnel left open by looters, the monumental artwork depicts human figures in a mythological setting, suggesting these may be deified rulers.

“This is a unique find. It is a beautiful work of art and it tells us so much about the function and meaning of the building, which was what we were looking for,” Estrada-Belli, a professor at Tulane University’s anthropology department, said.

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Painted in red, with details in blue, yellow and green, the stucco frieze is elaborately descriptive. It shows three human figures wearing bird headdresses and jade jewels. They are seated cross-legged on top of the head of a mountain spirit called witz.

A cartouche on the headdress contains glyphs identifying each individual by name, but only the central figure’s name is now readable. It says: Och Chan Yopaat, meaning “The Storm God enters the sky.”

Below the main character, two feathered serpents emerge from the mountain spirit and form an arch with their bodies. Under each of them is a seated figure of an aged god holding a sign that reads “First tamale.”

In front of the serpents’ mouths are the two additional human figures, also seated on mountain spirit heads.

An inscription of 30 glyphs in a band that runs at the base of the structure reveals the building was commissioned by Ajwosaj Chan K’inich, the ruler of Naranjo, a powerful kingdom to the south of Holmul in the northeast of Guatemala.

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According to Alex Tokovinine, a Harvard University Maya epigrapher, the text places the building in the decade of the 590s. It also reveals a power struggle between two rival kingdoms — Tikal and the Snake Lords — fighting for control of the region.

Homul, the city-state where the frieze was found, once belonged to Tikal’s kingdom, but its rulers switched sides. In this view, the frieze would be a tribute to Homul’s defection.

Indeed, in the inscription, Ajwosaj, who was a vassal of the Snake Lords, claims to have restored the local ruling line and patron deities.

“Ajwosaj was one of the greatest rulers of Naranjo. The new inscription provides the first glimpse of the remarkable extent of Ajwosaj’s political and religious authority,” Tokovinine said.

It isn’t the first finding made by Estrada-Belli and his team at the mysterious building. Last year, the archaeologist unearthed a burial in cavity dug into the stairway leading up to the building. It contained the skeleton of an adult male accompanied by 28 ceramic vessels and a wooden funerary mask.

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Preserved by large limestone slabs that kept the tomb free of debris, the individual had the incisor and canine teeth drilled and filled with jade beads, while two miniature flower-shaped ear spools were also found nearby.

By the skeleton, the archaeologists also unearthed nine red-painted plates and one spouted tripod plate decorated with the image of the god of the underworld emerging from a shell.

According to Estrada-Belli, the unusually high number of vessels and the jade dental decorations indicate the individual was a member of the ruling class at Holmul.

The archaeologist hopes to return to the area in 2014 to continue exploring the building.

Image: The stucco relief found in the ancient Maya city of Holmul. Credit: Francisco Estrada-Belli.