Cornplanter was a diplomat and defender of Seneca land and culture who allied the Iroquois Confederacy with the fledgling U.S. after fighting for the British during the American Revolution. He arbitrated conflicts between Native Americans and settlers, though he later became disillusioned when the Nations were not treated equally and fairly. In 1796, Cornplanter and his heirs were granted three tracts of land by the state, one at present-day Oil City.