The Third English Civil War took place from 1649 to 1651, following the execution of King Charles I. It was primarily fought between the supporters of the monarchy, known as the Royalists, and the forces of the Parliamentarians, who sought to establish a republican government. The conflict arose as the Royalists attempted to regain power and restore the monarchy. The war culminated in the decisive battle of Worcester in September 1651, where the Parliamentarian forces, led by Oliver Cromwell, defeated the Royalists. This defeat effectively ended the Royalist cause and solidified the establishment of the Commonwealth of England, a republican government that lasted until the monarchy was restored in 1660.