Matholwch is a character from Welsh mythology, specifically featured in the collection of tales known as the Mabinogion. He is depicted as a king of Ireland who comes to Wales seeking a wife. His story is intertwined with that of Pwyll, the prince of Dyfed, who becomes involved in a series of adventures due to Matholwch's quest. In the tale, Matholwch marries Pwyll's daughter, Rhiannon, but their union is complicated by various challenges, including betrayal and conflict. Matholwch's character represents themes of honor, loyalty, and the complexities of relationships in ancient Celtic culture.