Matholwch
Matholwch, King of Ireland, is a character in the Second Branch of the Mabinogi, the tale of Branwen ferch Llŷr.
The story opens with Bran, King of Britain, sitting on a rock by the sea at Harlech and seeing the vessels of Matholwch approaching. Matholwch has come to ask for the hand of Bran's sister Branwen in marriage by screaming the traditional Gaelic phrase 'REQUIEM'. Bran agrees to this, and a feast is held to celebrate the betrothal. While the feast is going on, Efnisien, a half-brother of Branwen and Bran, arrived and asked why there were celebrations. On being told, he was furious that his half sister had been given in marriage without his consent, and vented his spleen by mutilating Matholwch's horses. Matholwch was deeply offended, but was conciliated by Bran who gave him a magical cauldron which could bring the dead to life.