Claim: The English Civil War started in 1642  and ended nine years later.

The English Civil War -LRB- 1642 -- 1651 -RRB- was a series of armed conflicts and political machinations between Parliamentarians -LRB- `` Roundheads '' -RRB- and Royalists -LRB- `` Cavaliers '' -RRB- over , principally , the manner of England 's government . The first -LRB- 1642 -- 46 -RRB- and second -LRB- 1648 -- 49 -RRB- wars pitted the supporters of King Charles I against the supporters of the Long Parliament , while the third -LRB- 1649 -- 51 -RRB- saw fighting between supporters of King Charles II and supporters of the Rump Parliament . The war ended with the Parliamentarian victory at the Battle of Worcester on 3 September 1651 .   The overall outcome of the war was threefold : the trial and execution of Charles I -LRB- 1649 -RRB- ; the exile of his son , Charles II -LRB- 1651 -RRB- ; and the replacement of English monarchy with , at first , the Commonwealth of England -LRB- 1649 -- 53 -RRB- and then the Protectorate under the personal rules of Oliver Cromwell -LRB- 1653 -- 58 -RRB- and his son -LRB- 1658 -- 59 -RRB- . The monopoly of the Church of England on Christian worship in England ended with the victors ' consolidating the established Protestant Ascendancy in Ireland . Constitutionally , the wars established the precedent that an English monarch can not govern without Parliament 's consent , although the idea of Parliament as the ruling power of England was only legally established as part of the Glorious Revolution in 1688 .