 In 1846 the Caddo along with several other tribes signed a treaty that made the Caddo a protectorate of the US and established framework of a legal system between the Caddo and the US.Tribal headquarters are in Binger, Oklahoma.The Wichita and Caddo both spoke Caddoan languages, as did the Kichai people, who were also indigenous to what is now Oklahoma and ultimately became part of the Wichita and Affiliated Tribes.