Original: The first ( 1642 -- 46 ) and second ( 1648 -- 49 ) civil wars pitted the supporters of King Charles I against the supporters of the Long Parliament , while the third war ( 1649 -- 51 ) saw fighting between supporters of King Charles II and supporters of the Rump Parliament .
Simplified: The Third Civil War ( 1649 - 1651 ) was fought between supporters of King Charles II and supporters of the Rump Parliament .