 He and his cousin Winchester created the governmental foundation of the Chickasaw Nation in Indian Territory (now known as Oklahoma).In the 1850s, Holmes Colbert helped write the constitution for their government , as after the Choctaw–Chickasaw Treaty of 1854, the Chickasaw constitution, establishing the nation as separate from the Choctaw, was signed in Tishomingo on the 30th of August, 1856.Colbert married Elizabeth Betsy Love, daughter of Henry W. Love and his wife Sarah Ann Moore.