Oneota is a designation archaeologists use to refer to a cultural complex that existed in the eastern plains and Great Lakes area of what is now occupied by the United States from around AD 900 to around 1650 or 1700. Based on classification defined in Gordon Willey and Philip Phillips' 1958 book Method and Theory in American Archaeology, the Oneota culture belongs to formative stage. The culture is believed to have transitioned into various Siouan cultures of the protohistoric and historic times, such as the Ioway. A long-accepted ancestry to the Ho-chunk has yet to be conclusively demonstrated.