by Brian Edward Rise
The mountain that was the site, according to the Historia Brittonum, of Arthur's eleventh victory over the Saxons. The location has been lost. Geoffrey of Monmouth connects it with the Dolorous Mountain and claims the Castle of Maidens stood upon it. More likely Castle Rock in Edinburgh, there is no reason to suppose this is anything but invention on Geoffrey's part as it is unlikely the Historia author had Edinburgh in mind.
The possibility exists that the name "Agned" is the result of scribal corruption and possibly refers to one or more battles in fifth century Gaul, which, as members of the Empire, the Britons took part in — or so their descendants claimed. The name "Breguoin" replaces or appears alongside "Agned" in several manuscripts. There is reason to believe it is probably Bremenium, the Roman fort of High Rochester, Northumberland. Welsh poetry transforms the name to Brewyn. Praises in verse to the Cumbrian king Urien speak of a battle in the derelict "cells of Brewyn." Legend may have shifted credit for the battle to Arthur, highlighting the composite nature of the myth versus the historical figure.