Henry VIII's sisters Mary and Margaret had several daughters. If Edward died, the throne would pass to a woman and the Tudor dynasty would end. Accordingly, King Henry did all he could to protect his son's health; the infant prince lived in safe seclusion until his father wed Katharine Parr. Henry's last wife became a beloved mother to Edward and he adopted the zealous Protestantism which she championed. He also grew close to his half-sister Elizabeth, with whom he shared a household for some years. His older half-sister, Mary, was an equally zealous Catholic; her religion and the vast difference in their ages prevented a close relationship. Edward became king at the age of 10, but he was a mere figurehead. His Seymour uncles battled with and ultimately lost the Protectorship to the ambitious John Dudley, duke of Northumberland. During his brief reign, Edward demonstrated impressive piety and intelligence. But his potential would never be realized. He died an agonizing death at 15, possibly from a combination of tuberculosis and the measles. Northumberland had persuaded him to leave the throne to his Protestant cousin, Lady Jane Grey. This decision begat one of the most tragic tales of Tudor England. ]