From the Beauforts, the royal line of England is descended. Through John Beaufort (Earl of Somerset, Marquis of Dorset), who married Richard's half-niece, Katherine became the ancestress of Henry the Seventh, and the Tudor line, also of the royal Stuart line of Scotland. Through Joan and Ralph Neville of Raby (Earl of Westmorland), Katherine was great-grandmother to Edward the Fourth, and Richard the Third.

Surely John of Gaunt and Katherine de Roet, the herald's daughter, fulfilled the ancient prophecy, "Thou shalt get kings though thou be none."