Forgive me for not knowing this, but why did Mary decide to let Elizabeth succeed her? Wouldn't she have been too worried about her religious beliefs? Seems like Mary would've worked too hard to restore Catholicism to just let it die out again. Did Mary go back to Henry's will and the 3rd Succession Act?
(I take my Tudor's one step at a time. I'm still on Henry's wives...then I can move on to Edward, Mary and Elizabeth!)