Tokhtamysh dreamt of emulating his ancestors and made plans to reunite the Golden Horde. In 1380, he invaded the Blue Horde by fording across the Volga, and defeated Mamai during the Second Battle of the Kalka River. The ruler of the Blue Horde, Mamai, was killed shortly after the Battle of Kulikovo, marking Tokhtamysh's victory and the reunification of the Golden Horde.