The Lakota acquired horses around 1740 and crossed the Missouri River shortly after, arriving in the Black Hills in 1775. Conflicts with the Cree and Chippewa, as well as the lure of the Great Plains buffalo herds, incited the Sioux to move farther west in the mid-17th century. About the Brule Sioux: The Siouan language family, including Lakota-Dakota-Nakota speakers, inhabited over 100 million acres in the upper Mississippi Region in the 16th and early 17th centuries.
