Once the alliance with General Vallejo was formed, Sem-Yeto and the Suisunes led many expeditions with the object of quelling the other tribes of the region, the "Wappo, the Satisyomis Sotoyomes, a Wappo tribe, and the Cainameros the South Pomo Indians of Cainama in the region toward Santa Rosa" who were attempting to throw off Mexican domination. Sem-Yeto led both military expeditions against the other tribes and some peacemaking missions. His main reputation was a man of peace. Sem-Yeto eventually helped to keep the peace between the region's Native Americans and the Mexicans. A peace treaty was signed in 1836.