The Horse Indians tells about the Comanche Indians who are responsible for populating the Pacific Northwest with horses brought to the New World by the Spanish Conquistadors in 1550 A.D. Comanche warriors drove thousands of Mustangs north to their Shoshoni Indian cousins and the Shoshonis, in turn, held trade fairs on a large island on the Snake River. In this way, horses were dispersed to many Indians from the surrounding tribes. The Arapaho, Bannock, and Flatheads came to trade and more. The Appaloosa Horse, for example, was prized by the Palouse and Nez Perce Indians. The Cayuse Pony was favored by the Cayuse Indians.