 In 598 Brandub defeated the Uí Néill High King Áed mac Ainmuirech of the Cenél Conaill at the Battle of Dún Bolg (Dunboyke, Wicklow Co.) and the high king was slain, stopping the southward expansion of the Uí Néill.The "Borúma Laigin" (Cattle Tribute of Leinster) and the annals record that the war was caused by Brandub's killing of Áed's son Cummascach in 597 at Dún Buchat.The "Borúma Laigin" gives much detail of this event.