It was a close call as ‘Bloody’ Queen Mary was near fanatical about restoring England to Roman Catholicism (RC) and wiping out the disgrace of her mother, Catherine’s forced divorce from Henry VIII. Elizabeth, her half-sister, was the sole daughter of Mary’s mother’s replacement, Anne Boleyn, and Elizabeth was quite a bit less inclined to RC although her life depended upon keeping the appearance of being RC.
If Elizabeth had indeed been executed herself, the next in line (1558) then would have been the other Queen Mary [Stuart (age 15)], acknowledged reigning Queen of Scotland, except that she was already married for 6 months to the crown prince of France. As another devout RC, she would have given Protestant-trending England a real lengthy bout of practicing RC monarchs. An interesting alt-hist speculation there!
Plenty of blood on Queen Elizabeth and the Protestant’s hands as well, and for centuries to come. All in all, a tragedy that England was lost to the Church.
One parallel or alternative history would be a situation where England remained Catholic while France became Protestant. England would have aligned with Spain and the Holy Roman Empire while France aligned with the Netherlands and the Lutheran principalities of northern and central Germany. Given a Catholic England, would the Irish have gone Protestant out of their hatred of the English? Would Scotland, aligned historically with France, and being fellow Protestants, attempted to overthrow the monarchy? Would English Protestants have fled to France and the Netherlands, as the Huguenots fled to England and other Protestant countries?