"Although Ante Structure was partially demolished by the final phase of construction in the East Court (ca. 650-800), another building belonging to the middle span of the Acropolis sequence has been discovered sealed beneath the final-phase Str. 10L-16, a large temple that is being excavated by Ricardo Agurcia. This earlier building, known as Rosalila, was a two-story, multiroomed structure. Its entire façade was decorated with elaborate stucco masks, once painted in brilliant colors."
Robert Sharer, The Ancient Maya, p. 313
NOTE: This photo is from the Copan Sculpture Museum, and is a full-scale reproduction of Rosalila as it might have looked when its colors were intact.