Francis John Byrne suggests that the root of this apparent confusion lay in the fact that the Uí Dúnlainge kings exercised little real authority due to the aggressions of their western neighbour Cerball mac Dúnlainge (died 888), King of Osraige.
Meanwhile, his ally Cerball mac Dúnlainge (died 888) of Osraige invaded Leinster from the west.
He reached Dún Bolg (Dunboyke, modern County Wicklow) where his camp was attacked by the Laigin who were at first successful, but in a counter-attack they were put to flight.
In the intervening period, Áed Findliath invaded Leinster in an attempt to impose his authority and he plundered the country and burned churches including Cell Ausili (Killashee, near Naas) in 874.
[5] Muiredach retaliated and led a force to attack the lands of the southern Ui Neill in 875.