Peredur son of Efrawg is one of the Three Welsh Romances associated with the Mabinogion. It tells a story roughly analogous to Chrétien de Troyes' unfinished romance Perceval, the Story of the Grail,
The mysterious severed head being shown to Peredur by the King in T. W. Rolleston's Myths and Legends of the Celtic Race (1910)