(The word "forced" evokes Uther's "enforced" marriage to
Ygerne, the corrupt patrimony Arthur's new doctrine of courtship is designed to repudiate.) The king himself speaks of lying by Guinevere's side (G, 576) in a way that suggests it is no euphemism.
The role of Arthur's mother,
Ygerne, in Geoffrey of Monmouth and in Wace, is examined by Martine Thiry-Stassin.
His father, Uther Pendragon, was transformed by the art of the magician, Merlin, into the likeness of
Ygerne's husband, and Arthur was the issue of this illicit love and supernatural delusion of a faithful wife [whose husband Uther had treacherously slain].