Mary I (18 February 1516 – 17 November 1558), also known as Mary Tudor, was Queen of England and Queen of Ireland from 6 July 1553 (de facto) or 19 July 1553 (de jure) until her death on 17 November 1558.
Mary, the fourth crowned monarch of the Tudor dynasty, after the uncrowned Jane Grey and before Elizabeth I, is remembered for briefly returning England to Roman Catholicism. To this end, she had almost three hundred religious dissenters executed; as a consequence, she is often known as Bloody Mary. Her reestablishment of Roman Catholicism was reversed by her successor and half-sister, Elizabeth I (1558–1603). Mary and Elizabeth were both first cousins once-removed of Mary, Queen of Scots, granddaughter of their aunt Margaret Tudor.