of Calakmul has been calculated at 1000/km2 (2564 per square mile) in the site core and 420/km2 (1076 per square mile) in the periphery (an area of . Calakmul was a true urban city and not just an elite centre surrounded by commoner residences. The site core of Calakmul was known in ancient times as Ox Te' Tuun ("Three Stones") which may have been because of the triadic pyramid Structure 2. The Calakmul kingdom included 20 secondary centres, among which were large cities such as La Muñeca, Naachtun, Sasilha, Oxpemul and Uxul. The total population of these secondary centres has been estimated at 200,000. The kingdom also included a large number of tertiary and quaternary sites, mostly fairly small and consisting of a number of groups arranged around courtyards, although there are also larger rural sites situated on ridges along the edges of the bajos that include temples, palaces and stelae. The total rural population of the kingdom is calculated at 1.5 million people. The entire population of the Calakmul kingdom, including the city itself and the rural population in the area of the regional state, is calculated at 1.75 million people in the Late Classic period. The Emblem Glyph of Calakmul has a greater distribution than the Emblem Glyph of any other Maya city. The Glyph is also found in more hieroglyphic texts than any other Emblem Glyph, including that of Tikal. Calakmul administered a large domain marked by the extensive distribution of their emblem glyph of the snake head sign, to be read "Kaan". Calakmul was the seat of what has been dubbed the Snake Kingdom. At times the city had governance over places as far away as 150 kilometers. Known rulers Emblem Glyph At Calakmul's peak in the 7th century, the polity was known as Kan. The Preclassic political state in the Mirador Basin also used the title Kan. There is the idea that, after the collapse of the Mirador state, its refugees migrated north towards Calakmul, where they founded a new Kan polity. However, epigraphical studies of the monuments at Calakmul show that prior to the 7th century AD the emblem glyph of Calakmul had nothing to do with a snake, but with a bat. It seems that a different polity ruled there. The Kan emblem glyph, before being associated with Calakmul, is found (once) at Dzibanché, a site more towards the east. Perhaps during the