The Annals of Tigernach record a siege of "Etain" in 638,[1] which has been interpreted as Northumbria's conquest of Eidyn (Edinburgh) during the reign of Oswald, marking the annexation of Gododdin territories to the south of the River Forth.
In 671, word reached Ecgfrith that the Picts, under the command of the Verturian king Drest mac Donuel, were preparing to rebel and overthrow the Northumbrian hegemony.
According to this account, Ecgfrith became aware of the Picts plans to overthrow the Northumbrian suzerainty and he hastily assembled an invasion force of horsemen.
He headed north, aided by his sub-king Beornhæth,[8] who historian James Fraser suggests may have ruled the southern Pictish kingdom of Niuduera, identified as being located in present-day Fife.
[7] As a work of hagiography, Vita Sancti Wilfrithi is not an ideal historical source and it has been suggested that its partisan treatment of Northumbrian history inspired Bede's Historia Ecclesiastica.