In July 6th 1553, at age 15 he died, probably from tuberculosis. Before he died, he and his Council wrote a "Devise for the Succession". This was an attempt to prevent the country returning to Catholicism. Edward named his cousin, Lady Jane Grey, as his heir and excluded his half-sisters, Mary and Elizabeth. However, this was disputed after his death; Jane was deposed by Mary within 13 days. Mary I reversed Edward's Protestant reforms, which nonetheless became the basis of the Elizabethan Religious Settlement of 1559.