Mary of Guelders was a 15th-century noblewoman born around 1434. She was the daughter of Arnold, Duke of Guelders and Catherine of Cleves. In 1449, she married James II of Scotland, becoming Queen consort. Mary played a significant role in Scottish politics during her husband's reign. After the death of James II in 1460, Mary served as regent for their son, James III of Scotland. Her regency was marked by political challenges, including conflicts with the nobility. Mary of Guelders passed away in 1463, leaving a legacy as a strong and influential figure in Scottish history.