The leadership of the southern branch rested with the rival Clann Cholmáin whose chief, Máel Sechnaill mac Máele Ruanaid, was High King of Ireland.
Even within the Síl nÁedo Sláine, Cináed and his kin had a rival in the shape of Tigernach mac Fócartai, king of Lagore.
He and his allies, say the Annals of Ulster, "plundered [the southern] Uí Néill from the Shannon to the sea" burning churches and settlements.
This is portrayed as a rebellion against Máel Sechnaill, but the target may well have been Cináed's local rival Tigernach whose crannog in Loch Gabhair was burned, along with the nearby church at Trevet.
According to saga material embedded in the Fragmentary Annals of Ireland, the Viking king Amlaíb was married to a daughter of Cináed, and killed his brother Auisle in an argument over her.