Corpus of Electronic Texts Edition
The Wooing of Emer by Cú Chulainn (Author: [unknown])

paragraph 35

‘Over the Great Secret of the men of Dea, i.e., a wonderful secret and a wonderful whisper. It is called the Marsh of Dolluid28 to-day. Dolluid, son of Carpre Niafer, was wounded by Matu. Before that, however, its name was Great Secret of the Men of Dea, because it was there that the gathering of the battle of Moytura was first planned by the Tuatha De Danann, for the purpose of throwing off the tribute which the Fomori exacted from them, viz., two-thirds of corn and milk and offspring.’