Chan Chak K'ak'nal Ajaw, also known as Lord Chac before the decipherment of his corresponding name glyphs, is identified as a ruler of the pre-Columbian Maya polity at Uxmal in the 10th century. During his rule, somewhere between 890-910 AD, some of the largest and most impressive buildings in Uxmal, such as the so-called Nunnery and the Governor's Palace, were built. An inscription at a large ballcourt in Uxmal, for playing the Mesoamerican ballgame, informs us it was dedicated in 901 during the reign of this king.
Glyphs
Hieroglyphs found in Uxmal reveal that an Uxmal ruler took the name “Lord Chac” about 900. Scholars have been able to identify a real historical king named Lord Chac from the inscriptions found on monuments in Uxmal. This is very important because Puuc sites are notable for their lack of inscriptions and hieroglyphic texts, so they provide very little historical information. Some of the stelae from Uxmal also mention the name of this ruler.