The outcome Change of the war was threefold : the trial Legal_rulings and execution Killing of Charles I ( 1649 ) ; the exile Departing of his son , Charles II ( 1651 ) ; and the replacement Change of English monarchy with , at first , the Commonwealth of England ( 1649–1653 ) and then the Protectorate under the personal rule Legal_rulings of Oliver Cromwell ( 1653–1658 ) and briefly his son Richard ( 1658–1659 ) .