Mary Tudor = Mary Stuart or not?

They were two different people, of more or less the same era.

Mary Tudor was the daughter of Henry VIII and Catherine of Aragon, and was raised as a staunch Catholic. As Mary I of England, she succeeeded her brother Edward VI (who died young and was the only son of Henry VIII to survive for any length of time) and became known as ‘bloody Mary’ for her anti-Protestant pogroms. (Henry VIII had established the Church of England as a non-Catholic church.) Mary Tudor died, childless, at the age of 42. When her half-sister Elizabeth I (daugher of H VIII and Anne Boleyn) came to the throne, the Church of England was re-establshed.

Mary Queen of Scots, or Mary I of Scotland (known in France as Marie Stuart), is the one who married the Dauphin of France, but was soon widowed. To make a long story short, she and Elizabeth I (they were contemporaries) did not get along, and after allegedely being involving in several attempts to overthrow Elizabeth and inherit the throne of England, Mary was put into custody and finally executed for treason.

It was a messy period in history.

Philippa Gregory has written many historical novels that bring this period alive.