He was supported by some of the Ulster noblemen, including Fergus mac Róich and Bricriu, as well as allies from the other Irish provinces and from Scotland.
He married Beiuda, daughter of king of Lochlann, and, reinforced with 20,000 Scandinavian warriors, set sail again.
Congal decided, rather than ravage his own country, to march on Tara and fight Lugaid Luaigne for the High Kingship of Ireland.
Congal accepted his overtures, but stripped him of the kingship of Ulster, giving it to his brother Ross Ruad.
[2] Congal ruled Ireland for fifteen or sixteen years, at the end of which he was killed by Lugaid Luaigne's grandson Dui Dallta Dedad.