Final answer:
Mary Tudor earned her nickname "Bloody Mary" for the many executions of Protestants she ordered during her reign as queen of England.
Step-by-step explanation:
Mary Tudor earned her nickname "Bloody Mary" due to the executions of Protestants that she ordered during her reign. She was the daughter of Henry VIII and his first wife Catherine, and she came to the throne after the death of her younger half-brother, Edward VI. Mary was a devout Catholic and sought to restore Catholicism in England, leading to the persecution and execution of Protestants.