Mary I , 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), after the uncrowned Lady Jane Grey, until her death on 17 November 1558.

Mary was the daughter of Henry VIII, by his first wife Catherine of Aragon. She is chiefly 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".

On July 25, 1554 Mary married the Spanish prince Philip, later Philip II of Spain, her cousin Charles V's only son. Their marriage, at Winchester Cathedral, took place just two days after their first meeting, and it was extremely unpopular with the English.

During her reign, Mary's weak health led her to suffer two false pregnancies. No child, however, was born, and Mary died at the age of 42, most likely of ovarian cancer. She was succeeded by her half-sister, who became Elizabeth I.