the pole claimed the territory for the British Crown and stated the NWC intended to build a trading post at the site. Thompson's pole and letter were intended for the traders of the Pacific Fur Company, an American rival of the NWC. Continuing downriver, Thompson stopped at Yellepit's village and discovered the flag and medal left by the Americans. Thompson found Yellepit very friendly and intelligent, even encouraging Thompson's plan to set up a nearby trading post. For various reasons the post was not built until 1818, when the NWC established Fort Nez Perces at the mouth of the Walla Walla River. During the summer of 1811, Thompson met also the Walla Walla head chief, Tumatapum, and his equal-ranking Quillquills Tuckapesten, Nimipu head chief, Ollicott, Cayuse head chief, and, probably, Kepowhan, Palus head chief, and Illim-Spokanee, Spokane head chief. The Walla Wallas eventually adopted maintaining cattle herds, going as far as New Helvetia in California during 1844 to secure additional livestock. An estimated 40 Walla Wallas, Nez Perce and Cayuse under Walla Walla chief Piupiumaksmaks went on the expedition south. En route the party gathered stray horses, not aware the strays were stolen. Negotiations at New Helvetia were held between one of Piupiumaksmaks' sons, Toayahnu, and an employee of Sutter. The two men entered a dispute, and Toayahnu was killed. Despite fears of retribution among Sutter's staff by the Walla Wallas, Piupiumaksmaks returned with a small band of warriors and families in 1846 and declared peaceable intentions. The returning party had members infected with measles, which began to spread across the Columbia Plateau, decimating indigenous populations. Smallpox and other diseases were also introduced into the area, increasing the Walla Wallas' population decline. Despite this, the Walla Wallas then held extensive herds of horses, being the "principal wealth" of the tribe. The Walla Walla were one of the tribal nations at the 1855 Walla Walla Council (along with the Cayuse, Nez Perce, Umatilla, and Yakama), which signed the Treaty of Walla Walla. Notable Walla Walla Piupiumaksmaks (Yellow Hawk) (d. 1855), head chieftain of Walla Wallas James Lavadour (b. 1951), painter and printmaker Dan Henderson (b. 1970), Olympic wrestler and mixed martial artist Charles Sams (b. circa 1970), director of the U. S. National Park Service References External links Confederated Tribes of the Umatilla Indian Reservation Native American tribes in Washington (state) Native American tribes in Oregon Indigenous peoples of the Northwest