Through the entire fifth and sixth century, very few battles are listed in the Annales Cambriae. There are of course the “Arthurian” battles of Badon and Camlann, but even if we can believe that they took place there is no way to corroborate that they happened in 516/7 and 537/8, respectively; they could be dated wrong by decades. The first event we can be confident of is the Battle of Arfderydd. It is listed at 573 in the Annales Cambriae along with the notice that Gwenddoleu died there. Even that late we can not trust it completely though, three decades later it misdates the Battle of Chester by at least a decade.
The annals also fail us in not giving any real context for the battle. As we will see below Peredur and Gwrgi were present at the battle and died in an unknown battle in 580. Another participant was Dunawt son of Pabo and the annals give his death at 595, but in both instances we are given nothing else, no useful information. To gain a better understanding of what was happening in the sixth-century North we will have to explore the smattering of information to be found in several less traditional sources.
The Life of Kentigern only mentions Arfderydd in passing. In one of the later episodes we are told that a half-insane man who had been living in the woods for twenty years was once in the service of Gwenddoleu as a bard. When his king was killed at Arfderydd, this Myrddin lost his mind and ran into the woods. Basically, all this source does is confirm everything in the annal and add the name of a bard. Myrddin might be interesting in his own right (as the literary forefather of the more famous Merlin) but is not much help here.
Trioedd Ynys Prydein
The battle is mentioned in four different places here. None of the triads give a clear picture of the battle itself, but overall they do tell us that Gwenddoleu was on one side and Cynfelyn, Dunawt Fawr, Peredur, and Gwrgi were on the other. Dreon, Dunawt Fawr, and Dinogad are also connected to the battle but their alliances are not given.
The battle is listed in another triad as one of the three futile battles of Welsh legend. However, it is one of the last, lastest, and least trustworthy sections of the triads. We have already seen with Y Gododdin and the Historia Brittonum materials that Gwynedd had been interested in developing a sense of unity against the English kingdoms during the ninth century. Could the entry have been influenced by that nationalistic movement? Possibly. One way or the other, though, it does not help us to understand the sixth century any better though.
What can we take away from this battle? It was mentioned in several sources early on, which made it impossible for the Gwynedd editors to alter the fact that British kings had fought against British kings. Otherwise it might have suffered the same fate as Catraeth and confused British historians even more
Dr. Miller did a wonderful job of piecing together a reasonable scheme, but in the end she had to admit that there was no way of being certain about who was on whose side and why. As quickly as things may have changed in the period, the present author is not even certain that sort of information would be all that useful even if it were possible.
We can be certain of several broader items, though. For one, we can now add Arfderyö to the short list of battles we know much about in the sixth century – along with Catraeth. Arthuret seems to be an accepted spot for the battle, too, because the connection is made for us in the Vita Kentigerni. We also know that both battles were fought primarily between British kings.
Second, there are the distances involved which we can see by the participants. Traditionally Gwrgi and Peredur have always been connected with York; in the Welsh Arthurian stories Peredur’s father is Efrawc which is derived from the Latin word for York, Eburacum, called Ebrauc in the Historia Brittonum list of civitates.
The connection of Peredur and Gwrgi to late sixth-century York had made no sense up until the last couple of decades because York had been within the borders of Deira, and Deira was traditionally founded decades before Arfderydd or the deaths of Peredur and Gwrgi. However, now that we understand Germanic kingships were only forming in the mid-sixth century and that the British kingdoms were still dominant into the late sixth century, the association makes a little more sense; York had not yet been absorbed into Deira during the brothers’ lifetimes. We will see below when and how York ended as a kingdom, but for now this piece of information is mainly useful as a clue about politics in the last third of the century.
Dunawt Fawr has been tentatively connected with modern Dent, also in Yorkshire, because of an allusion in Eddius’ Vita Wilfridi to regio Dunotinga which was given to the church of Ripon in 675. It is tentative because Dunawt was not an uncommon name. However, Dunawt spent his career allied with Gwallog and fighting Owain and Pasgen the sons of Urien, and all three of them were from the same area.
The other names – Gwenddoleu, Dreon, and Dinogad – are people we can only guess generally about. Hector Chadwick and William Skene placed Gwenddoleu’s hall a few miles north of Arthuret. Dreon is as yet unidentified, while Dinogad might have been the son of Cynan Garwyn somewhere in Powys.
Even a Dinogad from northeastern Wales makes sense with what we have already learned about the late sixth century. Politics had already advanced well beyond cattle stealing and alliances went beyond standing together against a common enemy.
 Over the decades, estimates have put Badon as early as 478 and most scholars have hovered around 500, potentially making the Annales Cambriae not up to forty years off.
 Dr. Molly Miller has written the only serious exploration of the battle; Miller, “The Commanders of Arthuret”, TCWAAS 75 (Kendall, 1975), 96-117.
 As Bromwich pointed out, the entry uses the form Merlinus for Myrddin; Trioedd Ynys Prydein: The Welsh Triads, trans. and ed. Rachel Bromwich, (Cardiff, rev. 1978), 208.
 Ibid, 29, 31W, and 44.
 Ibid, 31W and 44.
 Ibid, 84.
 Ibid, xx-xxi, xxvi.
 Miller, “The Commanders of Arthuret”, TCWAAS 75 (Kendall, 1975), 96-117.
 Trioedd Ynys Prydein: The Welsh Triads, trans. and ed. Rachel Bromwich, (Cardiff, rev. 1978), 489.
 Eddius Stephanus: Life of Wilfrid, trans. James Francis Webb, ed. David Hugh Farmer, The Age of Bede, (Harmondsworth, rev. 1983), 126.
 Ibid, 396.
 Canu Llywarch Hen, ed. Sir Ifor Williams, (Cardiff, 1960).
 Skene, Arthur and the Britons in Wales and Scotland, ed. Derek Bryce, (Lampeter, 1988), 23-5; H. Chadwick, Early Scotland: The Picts, the Scots, and the Welsh of Southern Scotland, (Cambridge, 1949), 143; H. Chadwick, The Growth of Literature, (Cambridge, 1932), 109 and 111 fn. 4.
 “Dinogad”, Oxford Dictionary of National Biography, (Oxford, 2004), Web.