The Brut y Tywysogion ‘Chronicle of the Princes’ is a late 13th to early 14th century Welsh chronicle translated from a now lost Latin text. It is of limited use to those interested in the Old North as it mostly deals with events in Wales itself, but some of the early entries refer to northern events.

721And then died Beli son of Elffin [Elfin]*
 *both kings of Al Clud
736And then died Owein* king of the Picts [y picteit]
 *this is probably Eógan mac Muiredaig, who occurs in some Scottish Chronicles as a king of Dál Riata.
750Seven hundred and fifty was the age of Christ when the contest between the Britons [brytanyeit] and the Picts in the battle of Maes y Dawg1 [maes y daʋc], and the Britons slew Talorcan [Talargan], king of the Picts. And then Teudur [Teʋdʋr] son of Beli2 died.
 1. called Mocetauc in the Annales Cambriae and identified with Mugdock. 2. kings of Al Clud.
860Eight hundred and sixty was the age of Christ when the battle of Cryn Onnen [kryn onnen]1 occurred and the fort of Alclud [kaer Alclut]2 was ruined by the pagans [paganyeit].3
 1. literally ‘the quaking ash’. 2. Dumbarton Rock. 3. Viking raiders.