Three Bull-Protectors of the Island of Britain

Cynfawr Host-Protector, son of Cynwyd Cynwydion; Gwenddolau, son of Ceidiaw; and Urien, son of Cynfarch.

Sources
Red Book of Hergest | C. 1425
Text of the Mabinogion and Other Welsh Tales | John Rhys, 1887