Lady Jane Grey (1536/1537 – 12 February 1554), also known as Lady Jane Dudley or the Nine-Day Queen, was an English noblewoman and de facto monarch of England and Ireland from 10 July until 19 July 1553.
The great-granddaughter of Henry VII through his younger daughter Mary, Jane was a first cousin once removed of Edward VI. In May 1553, she was married to Lord Guildford Dudley, a younger son of Edward's chief minister, John Dudley, Duke of Northumberland. When the 15-year-old king lay dying in June 1553, he nominated Jane as successor to the Crown in his will, thus subverting the claims of his half-sisters Mary and Elizabeth under the Third Succession Act. Jane was imprisoned in the Tower of London when the Privy Council decided to change sides and proclaim Mary as queen on 19 July 1553. Jane was convicted of high treason in November 1553, which carried a sentence of death, although her life was initially spared. Wyatt's rebellion of January and February 1554 against Queen Mary I's plans to marry Philip of Spain led to the execution of both Jane and her husband.