Although some evidence exists of occupation during the Late Archaic period (around 1200 BCE) in and around the site, Cahokia as it is now defined was settled around 600 CE during the Late Woodland period. Mound building at this location began with the emergent Mississippian cultural period, about the 9th century CE. The inhabitants left no written records beyond symbols on pottery, shell, copper, wood, and stone, but the elaborately planned community, woodhenge, mounds, and burials reveal a complex and sophisticated society.