King Diarmait mac Cerbaill in 555 or 558, and Diarmait himself was killed by a Cruthin over-king of Ulster, Áed Dub mac Suibni, in 565. In 563, according to the Annals of Ulster, an apparent internal struggle amongst the Cruthin resulted in Báetán mac Cinn making a deal with the Northern Uí Néill, promising them the territories of Ard Eólairg (Magilligan peninsula) and the Lee, both west of the River Bann in County Londonderry. As a result, the battle of Móin Daire Lothair (modern-day Moneymore) was fought between them and an alliance of Cruthin kings, in which the Cruthin suffered a devastating defeat. Afterwards the Northern Uí Néill settled their Airgíalla allies in the Cruthin territory of Eilne, which lay between the River Bann and the River Bush. The defeated Cruthin alliance meanwhile consolidated itself within the Dál nAraidi dynasty. Their most powerful historical king was Fiachnae mac Báetáin, King of Ulster and effective High King of Ireland. Under their king, Congal Cláen, they were routed by the Uí Néill at Dún Cethirnn (between Limavady and Coleraine) in 629, although Congal survived. The same year, the Cruthin king Mael Caích defeated Connad Cerr of the Dál Riata at Fid Eóin, but in 637 an alliance between Congal Cláen and Domnall Brecc of the Dál Riata was defeated, and Congal was killed, by Domnall mac Aedo of the northern Uí Néill at Mag Roth (Moira, County Down), establishing the supremacy of the Uí Neill in the north. In 681 another Dál nAraide king, Dúngal Eilni, and his allies were killed by the Uí Néill in what the annals call "the burning of the kings at Dún Cethirnn". The ethnic term "Cruthin" was by this stage giving way to the dynastic name of the Dál nAraide. The Annals record a battle between the Cruthin and the Ulaid at Belfast in 668, but the last use of the term is in 773, when the death of Flathruae mac Fiachrach, "rex Cruithne", is noted. By the twelfth century it had fallen into disuse as an ethnonym, and was remembered only as an alternative name for the Dál nAraide. The Pictish Chronicle names the first king of the Picts as the eponymous "Cruidne filius Cinge". Possible relationship to other groups Early Irish writers used the name to refer to both the north-eastern Irish group and to the Picts of Scotland. Likewise, the Scottish Gaelic word