The political movement that emerged in opposition to the monarchy in England was the English Civil War. This conflict, which lasted from 1642 to 1651, saw Parliamentarians (Roundheads) opposing Royalists (Cavaliers) over issues of governance and authority. Discontent with King Charles I's authoritarian rule and desire for greater parliamentary power spurred the conflict. Ultimately, the war led to the temporary overthrow of the monarchy and the establishment of the Commonwealth under Oliver Cromwell, reshaping England's political landscape and paving the way for later constitutional monarchy.