Cynfarch Oer is a character from Welsh mythology, often associated with the legendary figure of King Arthur. He is known as a warrior and a leader, appearing in various tales that highlight his bravery and loyalty. Cynfarch Oer is sometimes depicted as a member of the Culhwch and Olwen story, which is one of the earliest tales in the Mabinogion. In some accounts, Cynfarch Oer is portrayed as the father of Cynfarch, a significant figure in the lineage of Welsh heroes. His stories reflect themes of honor and valor, common in the folklore of Britain. These narratives contribute to the rich tapestry of Welsh cultural heritage.