One of the goals in carrying out archaeological work on Temple XIII was to get to know its construction sequence and the way it was built on the skirt of the hill that it abuts. Work was started with the digging of two approach trenches, with the dual purpose of locating the contours of the temple's substructure and its main stairway. In continuing the exploration of the first two levels that had been initiated by Jorge Acosta in 1973, it was possible to locate the remains of the totally collapsed main stairway. As cleanup work was started, we located a small blocked-up door on the vertical section of the substructure's second level, some 2.80 m. over the level of the Plaza.
After removing the masonry that blocked the way, a narrow corridor was uncovered, six meters long with a north-south orientation, which led to one of the best preserved galleries in all of Palenque. This gallery was found completely free of debris. Oriented east-west and measuring 15 meters in length, it was built with large blocks of limestone.
The southern end comprises three chambers, the first and the last of which were empty, while the central one was blocked by perfectly placed stonework finished with a coat of stucco that still retained remnants of black pigment. The limestone lintel indicated that the chamber was once functional before being completely sealed up. A noteworthy element here is a cornice that caps the walls of the facade, made of several layers of thin slabs, an arrangement which brings to mind similar solutions at several temples at the site. Portions of this cornice had fallen down and had to be rebuilt and restored.
To the southeast and southwest of the gallery, two completely sealed doorways were found, while two additional sealed doorways were found in the gallery's east and west ends. The narrow corridor, the gallery and the chambers at its ends all feature the Maya arch, so common at Palenque and other Maya sites.
At the northern end of the gallery, the large limestone blocks used for its construction can be seen. Noteworthy here are the remains of a stucco coating with the imprints of human hands, found to the right of the section of the gallery where the narrow corridor ends. An important architectural element that must be mentioned here is the fact that the narrow corridor was once much broader, as can be observed in a construction juncture in the inner face of the gallery. The corridor's width originally coincided with the breadth of the central chamber.
The inner building presented no finishings at all, save for some remains in the upper and lower portions of the chambers.
Despite the good state of preservation of the substructure, at the beginning of May, 1994, we started cleanup and consolidation work on the outside of Temple XIII, with a view to stopping the constant rainwater seepage into the substructure.
One of the things that we found most remarkable was the presence of remnants of charcoal located at the foot and on the upper portion of the threshold to the sealed chamber. In the course of our work, many of us constantly wondered what the sealed chamber might contain. To get some answers and put speculation to rest, we decided to make a narrow cut on the upper left of the wall. Before deciding upon the penetration of a part of the wall that would allow us a glimpse into the chamber, we had to address several concerns. One of these was the possible presence of decoration on the inside of the wall to be penetrated. Normally, tombs in the Maya area and in other areas of Mesoamerica are laid out on a north-south axis. If this chamber had been reused as a mortuary chamber, there was a real risk of damaging a portion of the inner decoration of the chamber, given the fact that we would be excavating its northern wall. All necessary precautions were taken and a 15 cm. x 15 cm. penetration was made, through which we were able to glance for the first time in centuries upon one of the richest tombs of Palenque, second only to Pakal's.
Through the perforation, we could look into a perfectly vaulted chamber measuring 3.80 x 2.50 meters, most of the surface of which was occupied by a rectangular limestone sarcophagus. To the south, we could make out the main door of the chamber, as well as five steps that gave access to it.
Upon thus discovering the main access to the tomb through the perforation we had made, we assumed that the sealed doorways at the ends of the gallery might take us to it by locating an access gallery. Thus, we decided to explore the gallery's southeastern and southwestern doorways, since they displayed the same orientation as the main access to the tomb. After 15 days of explorations, we were able to ascertain that the doorways led to inner, ascending stairways which originally gave access to a construction built above. Through the use of test pits, we tried to locate the access to the chamber from the outside, but we had to abandon this endeavor after having excavated down for eight meters with negative results.
Given our fruitless efforts in trying to get to the chamber's access door, we decided to enter the tomb through its north wall. We thus proceeded to enlarge the small perforation, once we were satisfied that there was no decoration that would be destroyed on the inside of the wall.
The sarcophagus was painted red through the use of cinnabar, and it was carved in one single piece. On top of it lay a monolithic limestone slab 2.40 meters long, 1.18 meters wide and 10 centimeters thick. Standing roughly at the center of the slab was a lidded censer, and at the foot of this censer lay a small bone spindle whorl.