At the end of the 20th century, the Secretariat of Urban Development and Ecology carried out renovation work on the Old Archbishop's Palace, now the Art Museum of the Secretariat of Finance and Public Credit. This work caused some damage to the building, so the Subdirectorate of Archaeological Salvage, through archaeologists Guadalupe de la Peña Vilchez, Judith Padilla Yedra, and Pedro Francisco Sánchez Nava, conducted research and safeguarded the heritage in 1987.

Thanks to this work, a sloping wall was identified on the north and east sides of the first architectural section of the Temple of Tezcatlipoca. On July 1, 1988, in the adjoining courtyard under an oval fountain, a monolithic sculpture was found, a Temalácatl painted red with the representation, on the edge, of eleven triumphs of Moctezuma Ilhuicamina over other peoples, and a solar deity at the top. In its center is a hollow where there may have been a ring to which prisoners were tied before facing the Mexica warriors. These types of gladiatorial sacrifices were performed in honor of Xipe, the red Tezcatlipoca.

In 1994, archaeologists Laura del Olmo Frese and Diego Jiménez Badillo, from the Urban Archaeology Program, delimited the west and south sides of the temple of Tezcatlipoca. This intervention confirmed that the facade and the access stairway are located to the west.

The INAH decided to open six archaeological windows so that the public could see these pre-Hispanic remains, as well as some architectural evidence from New Spain.

The third window is located in a rectangular room adjoining the central porticoed courtyard. It is on the same axis as the previous window and shows the continuation of the Mexica building's staircase and its northern boundary, where it features a sloping alfarda and is topped by an architectural cube. A brazier was placed on the upper surface of the slope, which does not appear to have come from the excavations carried out on the property. This space also contains a sculpture in the shape of a standard-bearer, an architectural nail in the shape of a skull, a rectangular monolith representing projectile points, and an obsidian mirror.

Source: Raúl Barrera Rodríguez, director of the Urban Archaeology Program