Earl of Salisbury children: to his son Edward in 1485 until his execution for treason in 1499, and to Edward's sister, Margaret Pole, Countess of Salisbury, in 1513 until she was also executed, and the title again forfeited, in 1539. In 1605 the title was given to Robert Cecil, 1st Earl of Salisbury, a close advisor to James I. Cecil was a son of Queen Elizabeth I's chief advisor, William Cecil, 1st Baron Burghley. For information on this creation, see the Marquess of Salisbury. Some sources call Edward Plantagenet, 17th Earl of Warwick (1475–1499) also Earl of Salisbury, but "there is no reason
Earl of Birkenhead of Northampton, at the same time as he was given the earldom. The three peerages, like the earldom, were in the Peerage of the United Kingdom. Viscount Furneaux was used as the courtesy title by the heir apparent to the earldom; the title of this viscountcy derived from the maiden name of Lord Birkenhead's wife. He was succeeded by his only son, the second Earl. He was also a Conservative politician and held minor office under Neville Chamberlain and Winston Churchill. However, Lord Birkenhead is best remembered as a biographer. He was succeeded by his only son, the third Earl.