1,000-year-old altar and human sacrifices from Toltec Empire discovered in Mexico

Archaeologists in Mexico have unearthed a square stone altar used for human sacrifices during the Toltec Empire more than 1,000 years ago.

The altar, human bones, obsidian knives and ceramic vessels were discovered during excavation for a transportation project near the archaeological site of Tula, about 55 miles (88 kilometers) north of Mexico City.

In a translated statement posted Tuesday (March 24) by Mexico's National Institute of Anthropology and History (INAH), archaeologists described the altar — also called a momoztli in Nahuatl — as a three-layer construction of stones that measures about 10 square feet (1 square meter). Four human skulls and several human leg bones were recovered from three sides of the altar, likely from people who were sacrificed.

"We know that they are offerings because they are located specifically in certain sections of the feature, but we don't know if they have any other remains underground that cannot be physically seen," Víctor Francisco Heredia Guillén, the archaeologist who's coordinating the project, said in a translated video.

Archaeologists discovered the remains of walls around the altar, suggesting it was located in a courtyard. Additional rooms flanked the courtyard and may have been part of a palace or other residential structure housing ancient Tula's elite, Heredia said.

Between the fall of Teotihuacán around A.D. 550 and the rise of Tenochtitlán in 1325, Tula was an important Mesoamerican urban center and the capital of the Toltec Empire, which lasted from 950 to 1150. Located in Mexico's Hidalgo state, Tula was contemporary with the Maya site of Chichén Itzá in the Yucatán Peninsula. Tula boasts a large pyramid dedicated to the feathered serpent god Quetzalcoatl that is topped with four massive statues of Toltec warriors.

The newly discovered altar likely dates to the imperial period of Tula's occupation, according to the archaeologists. By that time, the Toltec had gained a reputation as fierce warriors, and the human sacrifices may have been enemies offered after the Toltec defeated them.

One of the skulls appears to still be attached to part of the spine, suggesting decapitation was part of the sacrificial ritual.

"In this case, although metal was already being worked in the postclassic period, we know that decapitations were still done here with obsidian or flint knives, and they left cut marks on the bones," Heredia said.

But additional research will be required to learn more about the sacrificial victims. Anthropological analysis should reveal whether the bones came from men or women, and chemical analysis may show whether the victims were local or came to Tula from afar, Heredia said.

"Each discovery like this expands our knowledge of one of the great civilizations of Mesoamerica," Claudia Curiel de Icaza, the Mexican secretary of culture, said in the statement.

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