Original: Initially established during the Pre-Classic period ( c. 2000 BC to 250 AD ) , according to the Mesoamerican chronology , many Maya cities reached their highest state development during the Classic period ( c. 250 AD to 900 AD ) , and continued throughout the Post-Classic period until the arrival of the Spanish .
Simplified: They keep a distinctive set of traditions and beliefs that are the result of joining pre-Columbian and post-Conquest ideologies ( and structured by the almost total adoption of Roman Catholicism ) .