AD. A branch of the Uí Erca Céin line of kings, the Síl Fingín, also twice held the overkingship of Dál nAraidi. After 750, the Uí Erca Céin became associated with the church of Bangor. At some point they disappear from Latharna and by the 14th century are found in the territory of Leath Cathail in central County Down. The Uí Erca Céin had five vassal tribes all of different origins: the Cenél Talain and Dál Fhocha nUchtar, both of whom appear to also have been of the Cruthin, and possibly refugees driven from their home that went to "Dercco Chen". A tradition of the Cenél Talain mentions that they had an ancestor who fought alongside Fiacha Araide, the eponymous ancestor of the Dál nAraidi; the Crothraidi, who according to tradition descended from Connacht, however migrated to Ulaid and after 600AD had joined the Uí Erca Céin; Crothraidi Buaingine, who are said to descend from Munster; and the Dál Coirb Fobair, a portion of whom where located in the south Antrim territory of Dál mBuinne, and are claimed to have descended from a Leinster prince called Cú Corb. History By the start of the historic period in Ireland in the 6th century, the over-kingdom of Ulaid was largely confined to east of the River Bann in north-eastern Ireland. The Cruthin however still held territory west of the Bann in County Londonderry, and their emergence may have concealed the dominance of earlier tribal groupings. 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. As a result, the battle of Móin Daire Lothair (modern-day Moneymore) took place 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. In 565, Áed Dub mac Suibni, king of Dál nAraidi and Ulaid, killed High King Diarmait mac Cerbaill at Raith Bec (Rathbeg, County Antrim). The Dál nAraidi king Congal Cáech took possession of the over-kingship of Ulaid in 626, and in 628 killed the High