Early in the morning of 5th September 1548, Catherine Parr, Queen Dowager and wife of Thomas Seymour, Baron Sudeley, died at Sudeley Castle just a few days after giving birth to her first child, a daughter Mary.
You can read more about Catherine’s death, and also the discovery of her remains in 1782, in my article from 2012 – 5 September 1548 – Death of Catherine Parr, Queen Dowager.
You can read more about Catherine herself in the following articles: