Archaeologists working on the Mexico City–Querétaro passenger rail project have uncovered an altar with skulls and bone offerings in Tula, the ancient capital of the Toltecs, a find that could sharpen understanding of the city’s layout.
The structure was discovered near Tula Chico inside the Archaeological Monuments Zone of Tula, about 300 meters (984 feet) from the site’s perimeter wall, during salvage work led by Mexico’s Culture Ministry and the National Institute of Anthropology and History.
Researchers believe the altar dates to the Tollan phase of the city, between A.D. 900 and 1150. Project coordinator Víctor Francisco Heredia Guillén said the structure measures about 1 meter (3.3 feet) on each side and appears to have had at least three low tiers without stairways.
He said the base was built with dressed stone, likely andesite, followed by modular stone slabs of the same material, while the upper section was finished with rounded stones and basalt.
Altar with skulls and bones offerings in the Toltec capital
Field archaeologist Emmanuel Hernández Zapata said the team first detected a compacted surface in a 1-square-meter (10.8-square-foot) test pit. After widening the excavation, researchers exposed one corner of the altar and then its other edges.
On three sides of the lower level, the team found offerings of human remains, including four skulls and long bones that may be femurs. Researchers suspect the fourth side may hold similar evidence. They also recovered ceramic vessels, including a black bowl with another vessel inside it, along with obsidian fragments and blades.
Two skulls were found at the base of the altar, one facing upward and another facing southwest. As the excavation moved deeper, archaeologists identified a compacted layer covered with what may be lime-and-sand plaster. Beneath it, they found two more incomplete human remains and additional vessels.
Lab analysis planned for human remains
Heredia Guillén said complete skeletons are unlikely because the offerings may have included only selected body parts. He said the remains will go to the project’s physical anthropology laboratory in the State of Mexico, where specialists will study age, gender, bone disease, and whether the individuals were decapitated.
He said one skull still appears to be attached to the spine, and noted that although metals were known in the Postclassic period, decapitations in the area were still carried out with obsidian or flint knives that left marks on bone.
Researchers also found wall remains that suggest the altar stood at the center of a courtyard, possibly within an elite residential or palace area.
Drawings and drone images have already been recorded for a digital site plan. Ceramic, stone, shell, spindle whorls, bone awls, and blades found at the site will also be analyzed.
