Cathal mac Áeda (before 722–737) was a king in southern Brega of the Uí Chernaig sept of Lagore of the Síl nÁedo Sláine.
[1] His father was slain at the Battle of Allen in the great defeat of the Ui Neill by the men of Leinster.
This theory proposes that Domnall attacked Cathal at Tailtiu, where the Uí Néill high kings traditionally held their main óenach.
[4] The Uí Chernaig sept had a feud with the Uí Chonaing sept of Cnogba (Knowth) in North Brega going back to the assassination of Cathal's grandfather Niall mac Cernaig Sotal (died 701) by Írgalach mac Conaing (died 702).
Tha family descended from Áed Laigin was a sub-sept of the Uí Chernaig known as the Sil Áeda Laigen.