Mary was born to Charles I, King of England and his wife, Henrietta, Princess of France in St James' Palace, London, England.Charles designated her Princess Royal in 1642, thus establishing the tradition that the eldest daughter of the British sovereign.
On 02 May 1642, she married Willem, Prince of Orange-Nassau in the Chapel Royal, Whitehall Palace, London, England.
In March 1647, her husband, Willem succeeded his father as stadholder. However, in November 1650, just after his attempt to capture Amsterdam from his political opponents, he died of smallpox. The couple's only child, Willem (later King William III of England), was born a week later.
In September 1660, she returned to England. She died of smallpox at Whitehall Palace, London and was buried in Westminster Abbey.