The Roundhead leader was Oliver Cromwell, an 8-letter name. Cromwell was an English military and political leader who served as Lord Protector of the Commonwealth of England, Scotland, and Ireland from 1653 until his death in 1658. He was one of the signatories of King Charles I's death warrant in 1649 and led the parliamentary forces during the English Civil War. He is also known for his role in the rule of the Commonwealth of England and the rise of the New Model Army.