The shrine
The shrine measures 31.9 by 12.1 metres (105 by 40 ft), with a maximum height of 8.9 metres (29 ft) excluding the roof comb. The exterior walls of the shrine are vertical, contrasting with the rest of the pyramid. The upper sections of the exterior walls formed a frieze, with three giant stone mosaic masks facing eastwards over the temple access. The central mask was directly over the outer doorway, while the other two were near the northern and southern extremes of the building's facadeThe shrine had three chambers situated one behind the other, each linked by a doorway with a lintel fashioned from sapodilla wood. These three rooms were the only accessible chambers in the entire pyramid temple. The lintel of the exterior doorway was plain but the two interior lintels were intricately carved. These two were removed in 1877 by Gustav Bernoulli and are now found in the Ethnographic Museum in Basel in Switzerland. The lintels were carved elsewhere and then moved to the pyramid, raised to the summit shrine and installed in prepared positions; this was a laborious task given that sapodilla wood weighs 1120 kg/m3 (69.1 lb/cubic foot). It was only after the installation of the lintels that the shrine was roofed and the roof comb built.
The hieroglyphic inscriptions on the sculpted lintels indicate that the temple was built in 741 AD, and radiocarbon dating of the lintels and wooden beams in the vaulting confirmed this, giving a result of 720±60 AD.
Lintel 3 is a wooden panel measuring 1.76 by 2.05 metres (5.8 by 6.7 ft) that is carved in low relief. It depicts the Tikal king Yik'in Chan K'awiil seated on a litter underneath the arch of a celestial serpent. The lintel was sculpted to mark his victory over the city of El Perú in 743. It has two panels of hieroglyphic script, containing a total of 64 glyphs.