The Nez Perce Indians of the Northwest Territory are credited with the development of Appaloosa Horses. The Appaloosa Horse is the state animal of Idaho.
The Lewis and Clark expedition made note of Appaloosas when they spent time with the Nez Perce Tribe in 1805. The Appaloosa gained the respect of the nation during the Nez Perce War in 1877, when 300 Nez Perce Indians outran 5000 US Calvary Troops to Canada. For detailed information on these events, I strongly suggest reading the following books.
More history can also be found by visiting the links to my site.