Katherine was Gaunt's mistress for about 25 years; when they married in 1396, they already had four children, including Henry's great-grandfather John Beaufort.
Katherine a fost metresa lui Gaunt timp de aproape 25 de ani; când s-au căsătorit în 1396 ei aveau deja patru copii, inclusiv pe străbunicul lui Henric, John Beaufort.