John Dudley was given the title of Duke of Northumberland in 1551. Dudley had great power in the reign of Edward VI. Dudley ruled by holding two offices: Lord President of the Council and Great Steward of the King's Household. Dudley obtained such an influence over Edward that the King was ready to make it appear that Dudley's ideas were actually his own. When Edward was dying, he and Dudley concocted a document which barred both Elizabeth and Mary (the remaining children of King Henry VIII of England) from the throne, in favour of Lady Jane Grey (who married Dudley's elder son, Guilford Dudley).
Dudley was forced to surrender to Mary I. He was arrested and executed for high treason in 1553. His younger son, Robert Dudley, Earl of Leicester, became powerful during the reign of Elizabeth I.