Why did Mary change from catholic to protestant?

Mary I of England, also known as "Bloody Mary," changed from Protestantism back to Catholicism primarily to restore her mother's religion and reverse the Protestant reforms instituted by her half-brother, Edward VI. Her reign was marked by a desire to re-establish Roman Catholicism as the state religion, which included the persecution of Protestant reformers. This shift reflected her personal beliefs and political motivations to consolidate power and unify the country under Catholicism. Ultimately, her efforts led to significant religious conflict during her reign.