Oliver Cromwell
From Tardis Wiki, the free Doctor Who reference
Oliver Cromwell was the leader of the English army in Ireland in September 1649. During the Siege of Drogheda, Cromwell attempted to kill the Seventh Doctor's companion Hex after he had insulted him. He failed to do so. (BFA: The Settling)
During World War II, "Cromwell" was the codeword for the German invasion of Britain. (NA: The Dying Days)