Ysbaddaden is a character from Welsh mythology, specifically from the tale “Culhwch and Olwen,” which is one of the stories found in the Mabinogion, a collection of medieval Welsh tales. In this story, Ysbaddaden is a giant and the chief antagonist.

Ysbaddaden is notable for his role in the tale as the father of Olwen, a beautiful maiden. According to the story, anyone who wishes to marry Olwen must first complete a series of near-impossible tasks set by Ysbaddaden. These tasks are his way of avoiding a prophecy that foretells his own death should his daughter ever marry.

When Culhwch, the protagonist of the story and a cousin of King Arthur, seeks Olwen’s hand in marriage, Ysbaddaden imposes a daunting series of forty impossible tasks or “anrhegion.” These tasks include hunting the fearsome boar Twrch Trwyth and retrieving items like the comb and scissors from between the ears of another fearsome boar, Ysgithyrwyn.

The tale of “Culhwch and Olwen” is one of the earliest Arthurian tales and one of the most intricate and expansive in Welsh literature. Ysbaddaden’s character, as the obstructive giant, serves as the catalyst for the adventure and the quests undertaken by Culhwch and his companions, including Arthur and his knights. The story is rich in Celtic mythology, featuring a wide array of magical creatures, challenges, and themes of heroism and perseverance.

The name “Ysbaddaden” may imply infertility and dermatitis, which are associated with gigantism caused by acromegaly. Additionally, the wounds inflicted on Ysbaddaden in the story can be interpreted as descriptions of arthritis and other features of acromegaly.