The English Civil War started in 1642  and ended nine years later.
The English Civil War ( 1642 -- 1651 ) was a series of armed conflicts and political machinations between Parliamentarians ( `` Roundheads '' ) and Royalists ( `` Cavaliers '' ) over , principally , the manner of England 's government . The war ended with the Parliamentarian victory at the Battle of Worcester on 3 September 1651 .