Jane Dudley, Duchess of Northumberland in the context of "Duke of Northumberland"

John Dudley, 1st Duke of Northumberland (1504 – 22 August 1553) was an English military officer and politician, who led the government of the young King Edward VI from 1550 until 1553, and unsuccessfully tried to install Lady Jane Grey on the English throne after the King's death. The son of Edmund Dudley, a minister of Henry VII executed by Henry VIII, John Dudley became the ward of Sir Edward Guildford at the age of seven. Dudley grew up in Guildford's household together with his future wife, Guildford's daughter Jane, with whom he was to have 13 children. Dudley served as Vice-Admiral and Lord High Admiral from 1537 until 1547, during which time he set novel standards of navy organisation and was an innovative commander at sea. He also developed a strong interest in overseas exploration. Dudley took part in the 1544 campaigns in Scotland and France and was one of Henry VIII's intimates in the last years of the reign. He was also a leader of the religious reform party at court.

In 1547, Dudley was created Earl of Warwick and, with the Duke of Somerset, England's Lord Protector, distinguished himself in the renewed Scottish war at the Battle of Pinkie Cleugh. During the country-wide uprisings of 1549 Dudley put down Kett's Rebellion in Norfolk. Convinced of the Protector's incompetence, he and other privy councillors forced Somerset out of office in October 1549. Having averted a conservative reaction in religion and a plot to destroy him alongside Somerset, Dudley emerged in early 1550 as de facto regent for the 12-year-old Edward VI. He reconciled himself with Somerset, who nevertheless soon began to intrigue against him and his policies. Somerset was executed on largely fabricated charges, three months after Dudley had been raised to the Dukedom of Northumberland in October 1551.