The Calmecac (kaɬˈmekak, from calmecatl meaning "line/grouping of houses/buildings" and by extension a scholarly campus) was a school for the sons of Aztec nobility (pīpiltin piːˈpiɬtin) in the Late Postclassic period of Mesoamerican history, where they would receive rigorous training in history, calendars, astronomy, religion, economy, law, ethics and warfare. The two main primary sources for information on the calmecac and telpochcalli are in Bernardino de Sahagún's Florentine Codex of the General History of the Things of New Spain (Books III, VI, and VIII) and part 3 of the Codex Mendoza. The calmecac of the Aztec capital, Tenochtitlan, was located in the ceremonial centre of the city and was dedicated to Quetzalcoatl. It was situated conveniently close to the Templo Mayor, where calmecac graduates destined for priesthood would perform the rituals they had been trained in. The main shrine was judged to be 150 feet tall and was a larger structure than the Templo Mayor. The calmecac's courtyard roof featured prominently visible motifs in the shape of spirals, each of which reached eight feet in height. Aztec rulers built their own individual versions of the calmecac upon the preceding one. These seven buildings were discovered in the mid 2000s when a team of archaeologists from the National Institute of Anthropology and History (INAH) began working on the site as part of History's Urban Archaeology Program (PAU) after the 1985 earthquake damaged the area. The calmecac was typically reserved for sons of Aztec noblemen, while the young commoner men, macehualtin, received military training in the Tēlpochcalli (teːɬpot͡ʃˈkalːi "house of youth"). The placement of noble youth in the telpochcalli might have been by lesser wives' or concubines' sons or younger sons, perhaps of commoner status so that the boys did not have to compete with noble youths in the calmecac. However, although the calmecac has been characterized as for elites only, Sahagun's account says that at times the macehualtin were assigned to the calmecac as well and trained for the priesthood.