Ruler of England on behalf of Edward VI (1551–53). He began his political career under Henry VIII and was a member of Edward VI’s Privy Council. As Earl of Warwick he sought to undermine Somerset’s power and was created Duke of Northumberland in 1551 shortly before ordering Somerset’s imprisonment and execution. The new government was committed to radical Protestantism and produced a new Prayer Book (1552), supported by a new Act of Uniformity prescribing penalties for not attending Church services. In 1552 Cranmer produced the Forty-Two Articles, a comprehensive statement of Protestant doctrine which formed the basis of the Thirty-Nine Articles (1571). Though posthumous tradition condemned Northumberland as an evil schemer, his regime promoted stability. He terminated the unsuccessful wars against France and Scotland initiated by Somerset and introduced several important financial reforms. Northumberland brought about his own downfall by trying to ensure the succession of Lady Jane Grey. He was executed and Mary, Henry VIII’s daughter, succeeded to the throne.