The Parliamentarians, commonly called Roundheads by their enemies and in modern historiography, were the supporters of the Parliament of England during the English Civil War (1642–1651). They fought against King Charles I of England and his supporters, known as the Cavaliers or Royalists, who claimed rule by absolute monarchy and the principle of the divine right of kings. The goal of the Roundheads was to give to Parliament the supreme control over executive administration of England.