The Reformation transformed English religion during the Tudor period. The five sovereigns, Henry VII, Henry VIII, Edward VI, Mary I, and Elizabeth I had entirely different approaches, with Henry VIII replacing the pope as the head of the Church of England but maintaining Catholic doctrines, Edward imposing a very strict Protestantism, Mary attempting to reinstate Catholicism, and Elizabeth arriving at a compromise position that defined the not-quite-Protestant Church of England. It began with the insistent demands of Henry VIII for an annulment of his marriage that Pope Clement VII refused to grant.[4]