The murals of Bonampak

Bonampak, in the rainforest of eastern Chiapas some 25–30 km south of Yaxchilán, had long been a satellite of its powerful neighbour. Its king Yajaw Chan Muwaan, who came to the throne in 776, recorded his wars on the carved lintels of Structure 1, a building of three rooms 16 m long: one shows him seizing a captive in January 787, another the king of Yaxchilán taking a prisoner four days earlier. According to the epigrapher Peter Mathews, Yajaw Chan Muwaan probably had the building constructed and painted.

Some 281 figures, many with name captions, cover the walls of the three rooms in bright colours, among them Maya blue. Room 1 shows the court with lords dressing, musicians and masked dancers, and the presentation of a royal child — long thought to be the heir, though Mary Miller and Claudia Brittenham argue that the child is a girl; Room 2 shows a battle and the display, torture and killing of captives; Room 3 a dance watched by the court and a scene of ritual bloodletting. The long text in Room 1 opens with a date that Peter Mathews, following Thompson, read as most probably 9.18.0.3.4 10 Kʼan 2 Kʼayab — 8 or 10 December 790 in the Julian calendar; a text in Room 1 records the dedication of the building, dated by Miller and Brittenham to 792 (791 in some accounts), and scholars date the paintings to about 790–792.

The murals are the last known work of the kingdom, which ceased to exist at the turn of the 9th century. Outsiders first saw them in 1946, when Lacandon Maya who still came to pray at the ruins led the American photographer Giles Healey to them; others, including Carlos Frey and John Bourne, also claimed the discovery. Infrared photography in 1996 revealed many glyphs that had become invisible.