The battle of Magh-Slecht, on the brink of Ath-derg, at Alt-na-helti, over Bealach-na-beithighe, is the name of this battle". The Annals of Connacht state- "A huge army was raised by Walter son of Richard Burke to attack Fedlim mac Cathail Chrobdeirg and Aed his son and Conchobar son of Tigernan O Ruairc, an army which for might and multitude had never been surpassed in Ireland, for it numbered twenty thousand to a man. They came to Mayo and Balla and passed through Leyney, which they plundered on all sides, to Achonry; and from there they sent messengers to the Ui Raigillig, bidding them to come and meet them at Cros Dairi Cain at the eastern end of the Brauslieve mountains in Tir Thuathail. The Ui Raigillig came to Clachan Mucada on Slieve Anierin, but turned back from there, not having effected a meeting with the Galls, and came to Soltin Gasain. And on that same day—a Friday, and the feast of Crosses in fact—Conchobar son of Tigernan O Ruairc mustered the men of Brefne and Conmaicne and all whom he could get, including Aed son of Fedlim O Conchobair and the chiefs of the Sil Murray and the rest of the men of Connacht. Now these are the best men that were with him:— Conchobair son of Tigernan O Ruairc king of Brefne, Cathal O Flaithbertaig, Murchad Finn O Fergail, Ruad in Feda O Flainn, Flann Mag Oirechtaig and Donn Oc, O Cellaig, the three sons of Mac Diarmata, Diarmait O Flannacain, Cathal son of Duarcan O hEgra, the two sons of Tigernan O Conchobair and Gilla na Naem O Taidc. But there were many of the youth of Connacht there besides these. The van of this host came upon the Ui Raigillig at Sailten Gassan and pursued them to Alt Tige Meg Currin. Here the new levies of the Muinter Raigillig turned upon this joint force and broke them thrice.