What Happened to Catherine Parr’s Daughter, Lady Mary Seymour? Elizabeth I’s Step-Sister

From History Calling

WHAT HAPPENED to Lady Mary Seymour, the only child of Queen Catherine Parr and Elizabeth I’s step-sister? Born on 30 August 1548, Mary was the child of Catherine’s fourth husband, Thomas Seymour, first Baron Seymour of Sudeley and was therefore a first cousin of King Edward VI, whose mother, Jane Seymour, had been the third wife of Henry VIII. Catherine, of course, had been his sixth, so little Mary was very well connected, and she was named after her other step-sister, Mary Tudor, later Mary I. Tragically, just days after her birth, the little girl’s mother died of childbed fever, leaving her great wealth to her husband. Mary was sent to live in the household of her uncle, Edward Seymour, Duke of Somerset, but after her father’s disgrace and execution the following year, the entirety of the Seymour-Parr wealth was forfeited, and she was left a penniless orphan. Taken in by her mother’s friend, Katherine Willoughby, Duchess of Suffolk, she disappears from the historical record in 1550 at the age of two. So what happened to Catherine Parr’s daughter? Did she grow up and marry during the reign of her step-sister, Elizabeth I, or did she die as a toddler like so many children of her era? In this Tudor history documentary from History Calling, we look into the mysterious disappearance of the almost royal Lady Mary Seymour, consider the theories as to what happened to her and ask: how strange is it that a girl like this seems to have dropped off the face of the planet?