Archaeologists from the National Insтιтute of Anthropology and History (INAH) have unearthed a stone box containing ceremonial offerings during excavations at Temple “I,” also known as the Great Basement, located within the Tlatelolco archaeological zone in present-day Mexico City.

Aerial view of the Tlatelolco Archaeological Zone, Mexico. Credit: ProtoplasmaKid / Wikimedia Commons / CC-BY-SA 4.0

This area, once the site of a pre-Columbian altepetl (city-state), was inhabited by the Tlatelolca people—Mexica, Nahuatl-speaking settlers who arrived in the region during the 13th century. Tlatelolco served as the sister city to Tenochтιтlan and later provided refuge to its inhabitants during the Spanish siege led by Hernán Cortés.

The recent discovery, marking 80 years of exploration at the site, consists of a stone box filled with ceremonial offerings placed between CE 1375 and 1418 to consecrate an expansion of Temple “I,” or the Great Basement.

Inside the box, archaeologists found 59 pocket knives, seven obsidian blades, and blocks of copal—items believed to have been used in acts of self-sacrifice by Tlatelolca priests and high-ranking officials.

This significant find is part of the ongoing Tlatelolco Project, launched in 1987 by renowned archaeologist Eduardo Matos Moctezuma. The project aims to deepen understanding of Tlatelolco’s history by comparing its material culture with that of its better-known counterpart, Tenochтιтlan.

The Great Basement—considered analogous to the House of the Eagles in Tenochтιтlan—is thought to have been a sacred space for the Tlatelolca military elite, possibly dedicated to the Black Tezcatlipoca, one of the most powerful deities in the Mexica pantheon. According to project director Salvador Guilliem Arroyo, the structure played a vital role in the ritual life of the Tlatelolca.

Leading the current excavations, archaeologists Francisco Javier Laue Padilla and Paola Silva Álvarez described the careful process of uncovering Offering 29, including the stratigraphy of the construction layers and the deliberate arrangement of the objects within the stone box.

Excavations have also revealed other important finds, such as Offering 28—ᴀssociated with the intensive burning of ceramic griddles—and numerous human burials. Many of the recently uncovered remains are believed to be victims of the cholera epidemic that struck the region in 1833.

More information: INAH