pull, they moved into new areas, traveling as far east as the Great Plains and as far south as California, to hunt, trade, fight, and capture slaves. Meanwhile, their herds multiplied rapidly, a combination of skillful breeding and periodic raids on other tribes. By the early 1800s, a Cayuse who owned only 15 to 20 horses was considered poor; wealthy families controlled 2,000 or more. Horses improved the range and effectiveness of war parties, making it possible for Cayuses to dominate their sedentary neighbors on the Columbia. They claimed ownership of The Dalles, the great fishery and trade emporium of the Columbia, forcing the weaker bands in that area to pay them tribute in the form of salmon and other goods. They frequently were in conflict fighting with Piute, Shoshone, and Bannock Tribes to the south and east referred to as the Snake people and other tribes such as the Blackfeet over territory and hunting sites. As white settlers moved into their territory in large numbers following the opening of the Oregon Trail in 1842, the Cayuse suffered. Even settlers passing through competed with them for game and water. Crowds of whites invaded the region during the California Gold Rush beginning in 1848 and when gold was discovered in Eastern Oregon in 1862. The tribe gained wide notoriety in the early days of the white settlement of the territory. In 1838, Marcus Whitman and his wife Narcissa established a mission among the Cayuse at Waiilatpu ("Place of the Rye Grass"), a site about seven miles from the present-day city of Walla Walla and about a quarter mile east of where the Cayuse Pásxa winter village was located. In 1847, a measles epidemic, suspected by some to be contracted from white settlers, resulted in high fatalities among the tribe. A small group of Cayuse, after putting Witmans medicine to the test with both sick and non sick individuals, and which all test individuals died, believed the missionaries were deliberately poisoning their native people, since a much higher percentage of the natives were dying from the measles than were the whites. In addition, cultural differences and settler encroachment had caused growing tensions. The Cayuse attacked the missionaries, killing Whitman and his wife Narcissa, and eleven others. They captured 54 European-American women and children and held them for ransom. They destroyed the mission buildings. This attack prompted an armed response by the United