▁from ▁the ▁contemporary ▁May a ▁city ▁of ▁Kam inal ju y u . ▁T az um al ▁is ▁ ▁south west ▁of ▁the ▁small ▁Late ▁Classic ▁site ▁of ▁Al um ul ung a . ▁ ▁History ▁Chal ch u apa ▁was ▁inhab ited ▁since ▁the ▁Pre class ic ▁period , ▁when ▁massive ▁construction ▁activity ▁took ▁place . ▁Ar ound ▁the ▁boundary ▁between ▁the ▁end ▁of ▁the ▁Late ▁Pre class ic ▁and ▁the ▁start ▁of ▁the ▁Early ▁Classic , ▁construction ▁at ▁T az um al ▁was ▁interrupted ▁by ▁the ▁er u ption ▁of ▁the ▁I lop ango ▁vol cano , ▁some ▁ ▁to ▁the ▁east ▁of ▁the ▁city . ▁This ▁er u ption ▁caused ▁a ▁hi atus ▁in ▁construction ▁activity ▁at ▁T az um al ▁that ▁may ▁have ▁last ed ▁several ▁gener ations . ▁Activity ▁res umed ▁during ▁the ▁Early ▁to ▁Middle ▁Classic ▁( c . ▁AD ▁ 2 5 0 - 6 5 0 ) ▁although ▁the ▁city ▁never ▁fully ▁recovered ▁to ▁its ▁Pre class ic ▁levels ▁of ▁activity . ▁The ▁T az um al ▁complex ▁came ▁closest ▁to ▁matching ▁the ▁enorm ous ▁structures ▁of ▁the ▁Pre class ic ▁period . ▁ ▁The ▁principal ▁structures ▁of ▁the ▁T az um al ▁group ▁date ▁to ▁the ▁Classic ▁period ▁( c . ▁AD ▁ 2 5 0 - 9 0 0 ) ▁of ▁Mes o amer ican ▁chron ology . ▁By ▁the ▁Late ▁Classic ▁( c . ▁AD ▁ 6 0 0 – 9 0 0 ) ▁T az um al ▁was ▁an ▁important ▁cer