[2] In 728 he acquired the throne of Leinster by slaying his elder brother Dúnchad mac Murchada (died 728) at the Battle of Ailenn (Co.Kildare).
[3] The weakness of the Ui Neill at this time led Cathal mac Finguine (died 742), the King of Munster, to assert his claims over Leinster.
[4] The location of the battle makes it probable that Cellach of the Osraige was the aggressor and was taking advantage of the rivalry of Faelan with Áed mac Colggen (died 738) of the Uí Cheinnselaig.
[6] The Annals of Tigernach claim it was his brother Bran Becc mac Murchada(died 738) whom the hostages were taken from but it was more probably Faelan.
He was the ancestor of the Uí Fáeláin sept of the Ui Dunlainge ruling at Naas in the eastern part of the Liffey plain, Airthir Liphi.