Peredur, son of Efrawg
Similar to Chrétien de Troyes' romance Perceval, the Story of the Grail, Peredur son of Efrawg is one of the three Welsh romances associated with the Mabinogion.
It is likely Peredur was a Brythonic prince ruling over a region in Northern England. He has a father, Efrawg, believed to be etymologically linked to York.
Efrawg dies when Peredur is young, and his mother raises him in isolation in woods. As he comes of age he meets a group of knights, and goes with them to the court of King Arthur.
At the court he suffers the ridicule of the knight Cei and sets off, promising to reclaim his honour. On his travels he meets two of his uncles. The first shows him how to bear arms, and instructs him not to question the significance of what he sees.
The second uncle reveals a severed head on a platter (perhaps the major departure from Chrétien's telling, which instead features the Holy Grail).
Peredur continues on his journeys, staying with the nine witches of Gloucester and falling in love with Angharad Golden-Hand. He returns to Arthur's court, and eventually learns that the severed head was that of his cousin.
The cousin had been killed by the witches of Gloucester. Aggrieved, Peredur avenges his family members, and returns home a hero.