A 38 mm badge with a magenta background and "Team Katherine Swynford".
Katherine Swynford was the mistress of John of Gaunt, the Duke of Lancaster. After John's second wife died he married Katherine and legitimised their four children who carried the name "Beaufort". It was partly through this line that Henry VII claimed the right to the throne of England.
After her death Katherine was buried in Lincoln cathedral, where her tomb still stands.
There's also a badge available for her second husband, John of Gaunt.