Summary from Wikipedia

Elizabeth was the only surviving child of Henry VIII and his second wife, Anne Boleyn. When Elizabeth was two years old, her parents' marriage was annulled, her mother was executed, and Elizabeth was declared illegitimate. Henry restored her to the line of succession when she was 10, via the Third Succession Act 1543. After Henry's death in 1547, Elizabeth's younger half-brother Edward VI ruled until his own death in 1553, bequeathing the crown to a Protestant cousin, Lady Jane Grey, and ignoring the claims of his two half-sisters, the Catholic Mary and the younger Elizabeth, in spite of statu ...