You will hopefully remember, from the above, that the first child by Katherine de Roet usually attributed to John of Gaunt may well have been legally (and biologically) her son by Sir Hugh Swynford. The other two Beaufort sons were childless and their sister married Ralph Neville, Earl of Westmorland, giving all of her descendants a different surname. So, by 1447, only the issue of John, Earl of Somerset were still Beauforts by name and that name is now in doubt for them, together with their Edward III descent. Given that one, or both, of Henry VII’s parents fall into this category, this is an important question.
We may have to wait some time to confirm Somerset’s biological father but Ashdown-Hill’s The Wars of The Roses has clarified the position of the Dukes of Somerset and their line. Pages 44-45 show that the Earl married Margaret Holland, great-granddaughter of Edward I and great-great-great-granddaughter of Henry III by the Lancaster (Crouchback) connection. Edmund, Earl of Kent was her great-grandfather, thus the Somersets have a slight claim to the throne. It is, however, inferior to those from Edward II’s other brothers and half-brothers, including the Mowbrays and Howards of Norfolk, as the table shows: