The war which ran from 1642-48 between King Charles I of England and many of his subjects, usually called 'Parliamentarians'. Charles had upset many people by seeming to want to rule England without a Parliament. It was also feared that he would make England a Catholic country. The Parliamentarians (Roundheads) fought the Royalists (Cavaliers), resulting in the defeat of the Royalists and the execution of the king. This was a terrible time in English history when even families members fought each other.