Queen Mary earned her nickname ' Bloody Mary' because of her persecution of Protestant heretics, whom she burned at the stake in the hundreds.
Mary I or Mary Tudor, was the Queen of England and Ireland from 1553 to her death. During her five-year-reign she ordered the death of more than 300 religious dissenters which died burned alive. Being burned at the stake was the typical punishment for heresy. Most heretics were burned and their ashes thrown into the river.
Mary I demanded the Restoration of Roman Catholicism in England and Ireland. Her Protestant opponents gave her the name 'Bloody Mary'.