This sept had their royal seat at Naas in the eastern part of the Liffey plain, Airthir Liphi.
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.
His predecessor as King of Leinster, Ailill mac Dúnlainge of the Uí Muiredaig sept had died in 871, however Muiredach mac Brain (died 885) of the Uí Dúnchada sept is associated with the Leinster forces in association with events in 870 and 875.
[5] In 874 the high king Áed Findliath (died 879) had invaded Leinster in an attempt to impose his authority and he plundered the country and burned churches including Cell Ausili.
[6] In 880 the new High King Flann Sinna (died 916) attacked Leinster and took hostages imposing his authority.