 Under the young King Edward VI John Dudley became one of the most powerful politicians , rising to be Earl of Warwick and later Duke of Northumberland . After the fall of Lord Protector Somerset in 1549 , John Dudley joined forces with his wife to promote his rehabilitation and a reconciliation between their families , which was symbolized by a marriage between their children . In the spring of 1553 Jane Dudley , Duchess of Northumberland became the mother @-@ in @-@ law of Lady Jane Grey , whom the Duke of Northumberland unsuccessfully tried to establish on the English throne after the death of Edward VI . Mary I being victorious , the Duchess sought frantically to save her husband 's life . Notwithstanding his and her son Guildford 's executions , she was successful in achieving the release of the rest of her family by befriending the Spanish noblemen who came to England with Philip of Spain . She died soon afterwards , aged 46 . 
