Gwenhwyfach

"This slap was recorded in the Bardic Triads as one of the Three Fatal Slaps", F. H. Townsend's illustration from The Misfortunes of Elphin (1897)

Gwenhwyfach (Middle Welsh: Gwenhwyvach, Middle Welsh: Gwenhwywach, or Middle Welsh: Gwenhwyach; sometimes anglicized to Guinevak) was a sister of Gwenhwyfar (Guinevere) in medieval Welsh Arthurian legend. The tradition surrounding her is preserved in fragmentary form in two Welsh Triads and the Mabinogi tale of Culhwch and Olwen.