He called Gwalchmai, the son of Gwyar, because he never returned home without achieving the adventure of which he went in quest. He was the best of footmen and the best of knights. He was nephew to Arthur, the son of his sister and his cousin.
And Arthur called Menw, the son of Teirgwaedd, in order that if they went into a savage country he might cast a charm and an illusion over them, so that none might see them, whilst they could see every one.
They journeyed until they came to a vast, open plain, wherein they saw a great castle, which was the fairest of the castles of the world. And they journeyed that day until the evening; and, when they thought they were nigh to the castle, they were no nearer to it than they had been in the morning. And the second and the third day they journeyed, and even then scarcely could they reach so far. And, when they came before the castle, they beheld a vast flock of sheep, which was boundless and without an end. And upon the top of a mound there was a herdsman keeping the sheep. And a rug made of skins was upon him; and by his side was a shaggy mastiff, larger than a steed nine winters old. Never had he lost even a lamb from his flock, much less a large sheep. He let no occasion ever pass without doing some hurt and harm. All the dead trees and bushes in the plain he burnt with his breath down to the very ground.
Then said Kai, "Gwrhyr Gwalstawt Ieithoedd, go thou, and salute yonder man."
"Kai," said he, "I engaged not to go farther than thou thyself."
"Let us go then, together," answered Kai.
Said Menw, the son of Teirgwaedd, "Fear not to go thither; for I will cast a spell upon the dog, so that he shall injure no one."
And they went up to the mound whereon the herdsman was; and they said to him, "Whose are the sheep that thou dost keep? and to whom does yonder castle belong?"
"Stupid are ye, truly. Through the whole world is it known that this is the castle of Yspaddaden Penkawr."
"And who art thou?"