Editing Conchobar mac Nessa (section)

===The Battle of Ros na Ríg===
After the ''Táin'', Conchobar falls ill and doesn't eat or sleep. The Ulaid ask Cathbad to find out what's wrong with their king. Conchobar tells Cathbad that he is ill because the other four provinces of Ireland have made war against him with impunity. Although he was victorious against Ailill and Medb, neither of them was killed in the battle, and he still lost his bull. He wants to make war against Connacht, but it is now winter, so Cathbad advises him to wait until summer when his men and horses will be fresh and energetic, and in the meantime, call on all his foreign allies to bring reinforcements. He sends word to [[Conall Cernach]], who is raising tribute in the [[List of islands of Scotland|Scottish islands]], and he raises a great fleet of the Ulaid's allies in [[Scandinavia]] and the [[Faroe Islands]] and brings them home to Ulster.

In response to this build-up, the other provinces mobilise. Eochu mac Luchta, king of Munster, convinces Ailill and Medb, very much against Medb's better judgement, to offer reparations to Conchobar. Ailill sends a man the Ulaid have reason to mistrust as their envoy to make the offer. Conchobar rejects the offer and says he will not be satisfied until he is able to pitch his tent anywhere in Ireland. When asked where he wants to pitch his tent that night, he selects Ros na Ríg ([[Rosnaree]]) on the [[River Boyne]]. A battle ensues at Ros na Ríg between the Ulaid on one side, and on the other side the kingdom of [[Meath (province)|Meath]], led by Conchobar's son-in-law [[Cairpre Nia Fer]], king of [[Hill of Tara|Tara]], and the Gailióin of [[Leinster]], led by their king Find mac Rossa. The battle goes badly for the Ulaid until Conall Cernach joins the fray because the wavering Ulstermen are too scared of him to retreat. Conall kills a thousand men in the battle. Cairpre Nia Fer kills 800 before Cú Chulainn kills him with a spear thrown from a distance, and then beheads him before his body hits the ground. The Gailióin retreat and the Ulaid take Tara. Erc, Cairpre's son and Conchobar's grandson, is installed as the new king of Tara. He swears allegiance to Conchobar and is given Cú Chulainn's daughter Fínscoth in marriage.<ref>E. Hogan (ed & trans), ''Cath Ruis na Ríg for Boinn'', Todd Lecture Series, 1892</ref>