Complex sentence: In 1867, Bullock became a resident of Helena, Montana, where he unsuccessfully ran for the Territorial Legislature and was elected to the Territorial Senate, serving in 1871 and 1872 and helped create Yellowstone National Park.
Split into simpler sentences: In 1867, Bullock became a resident of Helena, Montana, where he unsuccessfully ran for the Territorial Legislature. He was subsequently elected to the Territorial Senate, serving in 1871 and 1872 and helped create Yellowstone National Park.