Oliver Cromwell served as Lord Protector of England once the English Civil War finished in 1651. He was a leading figure in the Parliamentarian victory over the Royalists in the English Civil War and became the de facto ruler of England, Scotland, and Ireland. During his time as Lord Protector, Cromwell introduced a series of sweeping political, social, and economic reforms, and pursued an aggressive foreign policy. While he remains a controversial figure in British history, Cromwell is widely considered to be one of the most significant political figures in English history, and his legacy continues to be debated to this day.