"Only the central and northern masks within the lower register are still visible today on the west frieze. The end mask, with the axes in its eye associating it with the number six, represents the World Tree or Central Axis of the Maya world. The central mask seems to represent the Maya sun god. Between the masks is a framed profile of an ancestral deity.
In the upper register, a figure seated on a throne is visible. Although badly eroded, this figure probably represents a previous ruler or ancestor marking the lineage of the ruling family at Xunantunich. A dancing figure is visible next to the ruler. A fragment of a serpent-headed throne can be seen above the central mask. Three rulers or ancestors of the ruling family were probably portrayed on all sides of this building, each seated in a niche or atop a throne."
Belize Dept. of Archaeology, from sign at site