Corpus of Electronic Texts Edition
The Irish ordeals, Cormac's adventure in the Land of Promise, and the decision as to Cormac's sword (Author: Unknown)

section 32

That thing Cormac endured not. He went after them, and every one then followed Cormac. A great mist was brought upon them in the midst of the plain of the wall. Cormac found himself on a great plain alone. There was a large fortress in the midst of the plain with a wall of bronze around it. In the fortress was a house of white silver, and it was half-thatched with the wings of white birds. A fairy host of horsemen (was) haunting the house, with lapfuls of the wings of white birds in their bosoms to thatch the house. A gust of wind would still come to it, and still the wind would carry away all of it that had been thatched.