Henry VIII dies in jousting accident early 1536.
The infant Elizabeth is proclaimed Queen, with Anne Boleyn as Regent. This produces much the same reaction as Jane Grey's proclamation was later later to do OTL, and a full-blown rising starts in favour of Mary. However, Mary is in ASB's hands, as lady-in-waiting to her half-sister. A few days into the revolt, her sudden death is announced. The rebels proclaim Queen Margaret, who arrives in London a few days later, following collapse of AB's support.