The ancestors of Native Americans in the Great Basin were the Numic people. They were nomadic hunter-gatherers. The late introduction of the horse changed Indian culture. When the Saints arrived in the Great Basin they discovered an active slave trade among the Indians. Mountain men first developed relationships with Indians, which later led to favorable first impressions with the Latter-day Saints when they came into the Great Basin. Problems occurred when the Saints began establishing settlements outside the Salt Lake Valley, particularly in Utah Valley. It erupted into war. Seeing the atrocities that had been committed on both sides of the conflict, Brigham Young would ever after pursue a course of reconciliation and peace.