Corpus of Electronic Texts Edition
Cath Maige Tuired: The Second Battle of Mag Tuired (Author: [unknown])

section 78

Then he asked the sorcerer, whose name was Mathgen, what power he wielded. He answered that he would shake the mountains of Ireland beneath the Fomoire so that their summits would fall to the ground. And it would seem to them that the twelve chief mountains of the land of Ireland would be fighting on behalf of the Túatha Dé Danann: Slieve League, and Denda Ulad, and the Mourne Mountains, and Brí Erigi and Slieve Bloom and Slieve Snaght, Slemish and Blaíslíab and Nephin Mountain and Slíab Maccu Belgodon and the Curlieu hills and Croagh Patrick.