Queen Mary I, the monarch of England and Ireland since 1553, dies and is succeeded by her 25-year-old half-sister, Elizabeth. The two half-sisters, both daughters of King Henry VIII, had a stormy relationship during Mary's five-year reign. Mary, who was brought up as a Catholic, enacted pro-Catholic legislation and made efforts to restore the pope to supremacy in England. A Protestant rebellion ensued, and Queen Mary imprisoned Elizabeth, a Protestant, in the Tower of London on suspicion of complicity. After Mary's death, Elizabeth survived several Catholic plots against her; though her ascension was greeted with approval by most of England's lords, who were largely Protestant and hoped for greater religious tolerance under a Protestant queen. Under the early guidance of Secretary of State Sir William Cecil, Elizabeth repealed Mary's pro-Catholic legislation, established a permanent Protestant Church of England, and encouraged the Calvinist reformers in Scotland. In foreign affairs, Elizabeth practiced a policy of strengthening England's Protestant allies and dividing her foes. Elizabeth was opposed by the pope, who refused to recognize her legitimacy, and by Spain, a Catholic nation that was at the height of its power.