This altar is also known as na-chan by the locals and holds a two-headed image of the Cosmic Monster, one side in skeletal form signifying death and a living form on the other signifying rebirth. A special text appears at each side of the body; on the north side it reads “in the land of Yax Pasaj Chaan Yoaat"; on the south side is the glyph for "Yahau Chan Ah Bac", who is emerging from the body. This engraving of a non- king in a public monument gave the half brother the role of protagonist in the political affairs of Copan.

Copan's Dynasty lasted from about 465 A.D. to perhaps precisely 822 A.D. The date of the collapse is based on the texts inscribed on Altar L, a monument intended to commemorate Ukit Took', the reigning ruler who was never officially crowned. On this altar two figures are carved: the first one is that of Ukit Took' and the other is Yax Pasaj Chaan Yoaat. Although Yax Pasaj Chaan Yoaat is the official last king of the dynasty (as seen on Altar Q ) the text on the altar clearly states Ukit Took' as succeeding him to the throne. Altar L was never finished, so this points out to problems that arose suddenly around the Valley. What really did happen? We may never know for sure, but as research advances in Copan we are getting more clues, perhaps one day we may know what happened during Copan's final hour…

In between are the remaining 14 recognized rulers of the dynasty, each one sitting on a glyph with his respective name. Some of these rulers are quite well known, while about others threre isn't much information at all. From some of these rulers the only thing we have is the glyph they are sitting on, this could be due to the fact that any sculpture or architecture that bore their name, deeds or dates of ascension or period termination were destroyed, reused or recycled as monument fill for monumental architecture of later kings, as per the Maya's tradition.