History and Tradition
In the previous post in this series, Chronicles and Scribes, we saw how Middle Welsh versions of Geoffrey of Monmouth's Latin chronicle, Historia Regum Britanniae (History of the Kings of Britain), known as Brut y Brenhinedd (Chronicle of the Kings) became very popular in medieval Wales with the redactor adding minor corrections to errors possibly occurring in translation or additions appertaining to local tradition. One such version of the Brut y Brenhinedd that circulated in north east Wales was the Cotton Cleopatra (B) manuscript and a local variant known as Book of Basingwerk, both possibly originating from the same source document, contain the reference to Gweith Perllan Vangor, known as the Action (Contest) of Bangor Orchard, in place of the Battle of Chester, indicating that the redactor of the Brut, following local tradition, was aware that this conflict took place at Bangor not Chester.
Throughout this study I have emphasised that we are searching for vestiges of a monastery at Bangor-is-y-coed, and the annihilation of that monastery around the beginning of the 6th century AD. I have also stressed the need to apply caution in using traditional sources to form an historical account, which prompts the question “how reliable are handed-down references?” In answer we may have a reasonable degree of confidence in a source if other independent sources are known to exist. Of course this does not imply that if two or more local legends of an event are found to exist we should accept it as historical fact. However, it would be rash to dismiss this local lore out of hand; we should view these as indicators of a persistence of memory of such occurrences. Indeed, eminent scholars of early medieval Welsh Literature consider these traditional sources, although not history, as being consistent with historical events. 
It is now generally accepted that the Black Book manuscript was copied not at Basingwerk Abbey, Flintshire, north east Wales, but at Valle Crucis Abbey near Llangollen, in Denbighshire. Significantly, The Black Book of Basingwerk circulated immediately in the vicinity of Bangor Is-y-coed, situated some 25 miles from Basingwerk and only 15 miles from Valle Crucis, it is therefore a reasonable assumption to accept that it contains accurate local knowledge. 
In accepting that the Black Book of Basingwerk is correct in identifying the Battle of Chester with Gweith Perllan Vangor, the Action (Contest) of Bangor Orchard, ideally we should expect to find at least one other independent source for verification. We such find an account contained within the Trioedd Ynys Prydein, (Triads of the Island of Britain). The Triads are a series of sayings written in three consecutive lines, thought to have been a mnemonic device for Bards, considered by historians to be a semi-reliable source of information on the British Isles depicting people, events, and places from early Medieval Britain. There is no doubt that the Triads do contain insular accounts of historical events echoed in the early English sources, such as Bede and the Anglo Saxon Chronicle. However, they also contain a mythological element from Welsh poetry concerning Arthurian characters and others from the Mabinogion collection of tales. Additionally, some later Triads appear to have been influenced by the writings of Geoffrey of Monmouth. Therefore we must exercise a degree of caution to their reliability.
Peppered amongst these Triads can be found a group which refer to genuine historical events, if a little confused in places, concerning the Welsh conflict with Edwin of Diera. As we have seen above (see Part II - The Battle of Chester), Edwin is portrayed throughout Medieval Welsh poetry as symbolic of the English opponent, indeed Triad 26  refers to 'Edwin, king of Lloegr, as the third Great Oppression of Mon', (The Isle of Anglesey).
The same impression of Edwin is upheld throughout Geoffrey of Monmouth's History of the Kings of Britain. In Part III The Battle of Chester (2) we saw how according to Geoffrey of Monmouth and Reginald of Durham's Life of St Oswald, Edwin had been fostered in Gwynedd at Cadfan's court and befriended the Welsh king's son Cadwallon. Following a period of exile in Brittany, Cadwallon and Edwin's friendship falters over who will wear the crown of Britain and thus, Edwin's prolonged conflict against the North Wales king Cadwallon had begun. An example of the Welsh conflict with Edwin from this group of Triads is the 'Three Missions that were obtained from Powys',  which refers to the conflict between Cadwallon and Edwin at Meigin. At first glance this would appear to be the battle of Meigin recorded in the 10th century Annales Cambriae as 630 AD when 'on the Kalends of January the battle of Meigen took place' where Edwin and his two sons were killed by the forces of the victorious Cadwallon. The 9th century Historia Brittonum (often cited as Nennius) would appear to verify this account, recording that the two sons of Edwin fell with him in battle at Meicen, and his dynasty was exterminated because not one of his race escaped from that war; but all were slain by Cadwallon's army.
Although at odds with the Welsh sources, the English sources tend to agree on the date and location of Edwin's downfall. According to Bede, II.20, Edwin met his end in “a great battle being fought in the plain that is called Heathfield, Edwin was killed on the 12th of October, in the year of our Lord 633,” by Cadwallon allied with the Mercian warlord Penda. Following the battle Bede states that “King Edwin's head was brought to York.”  The Anglo Saxon Chronicle gives 633 AD as the year Edwin was slain on Hatfield Moor, near Doncaster, Yorkshire, on 14th October, only two days out from Bede's account.
However, allowing for the discrepancy in dates between the English and Welsh sources, this cannot be the same battle. Triad 55 appears to be referring to events having taken place in Powys  but the Historia Brittonum and Annales Cambriae, perhaps following the same Welsh source, appear to confuse this event with the conflict recorded in the English sources in which Edwin and his sons are killed by Cadwallon. It is possible, but unlikely, that there were two places named 'Meigen' in Dark Age Britain. It is also unlikely that the English name for 'Meigin' was 'Heathfield' as the Triad clearly identifies the site with Powys, whereas the battle site of the English sources are usually identified as Hatfield Moor, near Doncaster in South Yorkshire.
More likely the Welsh sources confused the death of Edwin at Heathfield with an earlier defeat at the hands of Cadwallon on the Powys borderlands. In the English sources, this is a major event, marking the death of king Edwin of Deira and his kin, whereas, in the Triads the battle of Meigin appears to be a minor battle in Powys, perhaps no more than a border skirmish with a local chieftain or even Edwin himself but certainly did not result in the death of the great 'Oppressor of the Welsh' and is notably absent from the Marwnad Cadwallon (The Elegy of Cadwallon) which includes a list of the Welsh leader's battles. We can justifiably expect the Welsh sources to record the death of Edwin as a major event but it is not noted as such in the accounts of the battle of Meigin.
Therefore, in essence, Triad 55 does appear to be of an historical nature which continues in the following Triads referring to events of the Welsh conflict with Northumbria:
Triad 62 Three Fettered War-Bands of the Islands of Britain mentions Cadwallon fighting with Serygei the Irishman at the Irishmens’ Rocks in Môn (Anglesey) and Belyn of Llyn fighting with Edwin at Bryn Edwin in Rhos, Flintshire, North Wales.
Triad 69 Three Defilements of the Severn records when Cadwallon went to the Action of Digoll with the forces of the Cymry with him against Edwin on the other side with the forces of Lloegr with him. And then the Severn was defiled from its source to its mouth; Annales Cambriae for the year 632 records the slaughter of the [river] Severn and the death of Idris, which is probably the same event referred to in the Triad.
In the middle of this group of Triads and in much the same vein in recalling historical events of the Welsh conflict with the English, we find Triad 60 Three Gate-Keepers of the Contest of Bangor Orchard in which we find an account of the same conflict referred to in the Brut y Brenhinedd that circulated in north east Wales, the Cotton Cleopatra (B) manuscript and a local variant known as the Black Book of Basingwerk. As stated above the local redactor of this version of the Brut, produced at Valle Crucis Abbey, only 15 miles from Bangor Is-y-coed, substitutes the Action of Bangor Orchard in place of the Battle of Chester, indicating local knowledge of the real site of the massacre of the holy men.
Three Gate-Keepers at the Action of Bangor Orchard:
Gwgon Red Sword,
and Madawg son of Rhun,
and Gwiawn son of Cyndrwyn.
And three others on the side of Lloegr:
Hawystyl the Arrogant,
and Gwaetcym Herwuden,
and Gwiner. 
In the next part of this examination of the Battle of Chester we will look at this Triad in more detail.
1. Jenny Rowland, Early Welsh Saga Poetry, D S Brewer, 1990, pp. 126 – 130, and Rachel Bromwich, "Trioedd Ynys Prydein" – The Triads of the Island of Britain, University of Wales Press, 2006, Third Edition, pp. 156 -160.]
2. See The Round Table Revealed Part V: Chronicle and Scribes
3. The Triads are numbered in accordance with Rachel Bromwich "Trioedd Ynys Prydein" – The Triads of the Island of Britain, University of Wales Press, 2006, Third Edition.
4. Bromwich, Ibid. Triad 55, p.156.
5. There is a tradition from Welsh poetry (Gofara Braint) that Edwin's head was taken to Aberffraw, Anglesey, the seat of the Kings of Gwynedd - see Gruffydd, R. Geraint. "Canu Cadwallon ap Cadfan" in Astudiaethau ar yr Hengerdd: Studies in Old Welsh Poetry, University of Wales Press, 1978.
6. Rachel Bromwich, Op. Cit. pp. 156 -160.
7. Bromwich, Ibid. Triad 60, p. 171.
* * *