c.570. Battle at Catraeth (Catterick): Gododdin against Rheged and Deirans (?)
This battle is known only from the Welsh poem Y Gododdin, which commemorates the British heroes of the tribe of Gododdin (centred on Edinburgh), some of whom seem to have died trying to recover Catraeth (probably Catterick in Yorkshire) from a force sometimes identified as Deiran and sometimes as British. The poem is a series of elegies on individual heroes, and since none of these heroes can be dated we cannot say when the battle took place.
The traditional date for the battle is c.600, presumably to fit the reign of Æthelfrith of Northumbria, who was remembered by Bede as the English ruler who ravaged the Britons more extensively than any other (HE, i.34). But there is no clear evidence for dating in the poem itself, and more recent theories have proposed dates of c.540 (Dumville, in Early Welsh Poetry and c.570 (Koch, at p.xxx). Since the arguments revolve around finally unanswerable questions about how much historical accuracy should be read into later Welsh poetry, and whether other poems with clearer historical references are describing the same events, we will probably never know the precise date of the battle.
J. Koch, The Gododdin of Aneirin: Text and Context from Dark Age North Britain (Cardiff: 1997)
B. Roberts, ed., Early Welsh Poetry: Studies in the Book of Aneirin (Aberystwyth: 1988)