Edward VI of England
He died when he was  years old, probably from tuberculosis. Before he died, Edward named his cousin, Lady Jane Grey, as his heir and excluded his half-sisters, Mary and Elizabeth. He was trying to prevent Mary, a Catholic, from returning the country to Catholicism. However, Mary overthrew Jane less than two weeks later and became the queen. Mary undid the reforms of Edward's reign, but Elizabeth restored them in 1559.