 The first recorded European to enter the region was Spanish Conquistador Hernando de Soto, who encountered many cultures of Caddoan languages-speakers, including the Caddo, Wichita, Pawnee, and Kichai peoples.Between AD 800 and 1450, much of the midwestern and southeastern US (including the eastern part of what is now Oklahoma) was home to a group of dynamic cultural communities that are generally known as the Mississippian culture.These cultures were agrarian, their communities often built ceremonial platform and burial mounds, and trade between communities was based on river travel.