|Yax Ak is known only from three, or possibly four, Tonina monuments at that document his capture. These monuments portray Yax Ak as a captive, and one of them (Tonina Monument 31) says that he was a vassal lord of the king of Palenque, K'inich Kan B'alam II. Monument 31 is one of six composite sculptures of captives that originally adorned the ballcourt at Tonina. The dates of capture of several of the other prisoners are known: they span the years AD 692-696, in the years leading up to the dedication of the ballcourt on 184.108.40.206.7, in AD 699. Presumably, therefore, Yax Ak was captured during the final decade of the seventh century, AD, and he was probably sacrificed when the ballcourt was dedicated. No birth date survives for Yax Ak, but most likely he was born during the latter half of the seventh century, AD.