But his ambition and violence made him deeply unpopular, and the failing health of Edward VI. opened up a serious prospect for Northumberland. He was only safe so long as he controlled the government, and prevented the administration of justice, and the knowledge that not only power but life was at stake drove him into a desperate plot for the retention of both. He could trade upon Edward's precocious hatred of Mary's religion, he could rely upon French fears of her Spanish inclinations, and the success which had attended his schemes in England deluded him into a belief that he could supplant the Tudor with a Dudley dynasty. His son Guilford Dudley was hastily married to Lady Jane Grey, the eldest granddaughter of Henry VIII.'s younger sister Mary. Henry's two daughters, Mary and Elizabeth, the descendants of his elder sister Margaret, and Lady Jane's mother, the duchess of Suffolk, were all to be passed over, and the succession was to be vested in Lady Jane and her heirs male. Edward was persuaded that he could devise the crown by will, the council and the judges were browbeaten into acquiescence, and three days after Edward's death (July 6, 1553), Lady Jane Grey was proclaimed queen in London. Northumberland had miscalculated the temper of the nation, and failed to kidnap Mary. She gathered her forces in Norfolk and Suffolk, Northumberland rode out from London to oppose her, but defection dogged his steps, and even in London Mary was proclaimed queen behind his back by his fellow-conspirators. Mary entered London amid unparalleled popular rejoicings, and Northumberland was sent to a well-deserved death on the scaffold. Queen Mary. Restoration of the old religion. Unpopularity of the Spanish marriage. Philip II.