Culhwch, son of Cilydd, a nobleman of Wales was counselled by his mother to seek Olwen as a bride. Fair Olwen, only daughter of the giant Ysbaddaden Who would never let her marry, for when she wed he'd die.
So Culhwch went to Arthur, his kinsman and his cousin To ask for aid in seeking fairest Olwen for his bride Arthur's knights they joined him: Kei, Bedwyr and Gawain With Menw the magician and Cynddylig as their guide
And so they travelled onwards to the lands of Ysbaddaden Where they came upon his castle, and rode their steeds inside. "Chief giant!" shouted Culhwch to the monster king before him "I've come for fairest Olwen, that your daughter be my bride."
"Before you have my daughter bring me Mabon son of Modron Who was taken from his mother even as his lips first cried." "I know that I can do so, 'though you think it be not easy." Said good Culhwch to the giant as he called the knights to ride.
So the sought the oldest animal, the Blackbird of Cilgwri, And said "Know ye of Mabon, stolen from his mother's side?" The Bird showed them an anvil that his beak had rendered small And said, "Though I am ancient, there are older hearts than I."
They found the Stag of Rhedynfre who stood beside a stump and asked him, "Know ye Mabon, stolen from his mother's side?" "This oak was once a sapling rooted first when I was young, But I'm not the oldest animal" the graceful stag replied.
So on the party travelled to the Eagle of Gwernabwy And asked him, "Know ye Mabon, stolen from his mother's side?" The Eagle showed a pebble that was once a mountain high, but he said, "Despite this evidence, one goes more deep than I."
They traveled to the water and the Salmon of Llyn Llyw. They said, "Know ye of Mabon, son of Modron and his bride?" "Indeed I've heard his wailing in his prison all these years, And for Arthur's faith and honour, his companions I will guide."
And so the Salmon led them up the river to a tower, Where they heard the lamentations of the prisoner inside. But the stonework of the castle couldn't stand before the army; Mabon pledged his life to Arthur, and homeward all did ride.
So Culhwch and companions went with speed to see the giant With elation in their hearts and lost Mabon at their side. They severed off the head of the oathbound Ysbaddaden, And that was how good Culhwch won fair Olwen for his bride.