Continued from Part II: The Battle of Chester
Reason for the Battle
Weltering amid warriors slain,
Spurn'd by steeds with bloody mane,
Slaughter'd down by heathen blade,
Bangor's peaceful monks are laid:
Word of parting rest unspoke,
Mass unsung, and bread unbroke;
For their souls for charity,
O miserere, Domine! 
The date the English arrived on the shore of the Irish Sea has long been the cause of debate between historians; if Æthelfrith's Northumbrians army had reached Chester they had certainly come along way from their Bernician homeland. What could have been his motive for venturing so far afield? Expansion of his kingdom seems unlikely, as although he was victorious in the slaughter of the British at the city of the Legion, Chester did not come under Northumbrian control at this time.
Drawing on Welsh traditional sources for his History of the Kings of Britain (c.1136), Geoffrey of Monmouth tells us that following the battle all the princes of the Britons met at Legecester (Chester) and made Cadwan (Cadfan) their king and under his command pursued Æthelfrith beyond the Humber. They prepared for battle but came to an agreement that Cadwan should enjoy the part of Britain this side of the Humber and Æthelfrith the part beyond it. In the meantime, Æthelfrith banished his own wife and married another. She, being with child, went to live with Cadwan in Gwynedd. She had a son called Edwin who grew up with Cadwan's son Cadwalla (Cadwallon). Needless to say, after a period of exile in Brittany, eventually Cadwalla and Edwin fall out over who will wear the crown of Britain and the Welsh campaign against Edwin's English begins.
Further references in early Welsh poetry to the name 'Edwin' appearing as symbolic of the English opponent in prolonged conflict against the North Wales king Cadwallon, ultimately ending in his defeat, e.g. a Triad included in The White Book of Rhydderch (Llyfr Gwyn Rhydderch c.1350) refers to Edwin, king of Lloegr, as the 'third Great Oppression of Mon', (The Isle of Anglessey). 
Geoffrey is not our only source for Edwin's fostering by king Cadfan of Gwynedd, indeed the tradition is recorded in the Triads of the Island of Britain (Trioedd Ynys Prydein). In addition to Geoffrey of Monmouth's account and reference to Edwin's exile in the Triads, we find a further tradition in the Life of Oswald, thought to be written by Reginald of Durham in 1165. This 'Life' is an account of Oswald the Northumbrian king who was killed at Oswestry in 642. Reginald's account tells of Edwin's residence in Wales and like Geoffrey places it after the Battle of Chester.
We cannot rule out the possibility that The Triads and Reginald of Durham were influenced by Geoffrey's story of Edwin's Welsh exile in his History of the Kings of Britain of course and may be treated with some caution as the account is absent from both the Welsh and Irish Annals, but Æthelfrith's pursuit of Edwin and his heirs in exile is documented by The Venerable Bede, which is an accepted historical account, who asserts that Edwin had spent long periods in exile before he came to the throne of Northumbria. 
Therefore on Bede's trusted account of Edwin's wanderings “through several places and kingdoms” it is not unreasonable to suggest the possibility that his exile could have included a stay in Wales. Edwin certainly appears to have spent sometime in the midland realm of Mercia as he married Cwenburh, daughter of king Cearl, and had two sons Osfrith and Eadfrith while in exile. Mercia may well have held an early close relationship with the north Welsh as they later formed a successful alliance under Cadwallon and Penda against the Northumbrians. An exile in North Wales could certainly have been a motive for Æthelfrith's attack on Chester, Edwin his target, in order to prevent him returning to the Deiran throne. Indeed, it is Æthelfrith's pursuit of Edwin, the Deiran heir, that ultimately brings about his own death; just a year after the Battle of Chester, the death of Æthelfrith is recorded when he is slain in battle on the east side of the river Idle in 617, on the borders of the kingdom of Mercia, after King Raedwald of East Anglia, refused to handover Edwin to the Northumbrians. 
The Welsh Annals record Edwin commencing his reign immediately after the battle at the river Idle in 617 and ending in 630:
630 - …........ On the Kalends of January the battle of Meigen; and there Edwin was killed with his two sons; but Cadwallon was the victor.
This victory, perhaps the pinnacle of Cadwallon's career, is recorded in the Welsh sources as Gweith Meigen in which a Welsh alliance 'supported by Penda, a most warlike man of the royal race of the Mercians', defeated Edwin of Northumbria, referred to in the English sources as the battle on the plain of Heathfield (Hatfield, near Doncaster) on 12th October 633.  It would appear that Cadwallon attempted to eradicate Edwin's dynasty; one of his sons Osfrith fell in the same battle and another Eadfrith was taken to Mercia but by the following year was also dead. Bede declared that it was Cadwallon's intention to exterminate the English race being “so barbarous in his disposition and behaviour, that he neither spared the female sex, nor the innocent age of children, but with savage cruelty put them to tormenting deaths, ravaging all their country for a long time, and resolving to cut off all the race of the English within the borders of Britain”. 
The following year Cadwallon's was slain at The battle of Cantscaul, which according to Bede is 'a place in the English tongue called Denises-burn, that is, Denis's-brook'.  The pagan king Penda continued the conflict with Northumbria pursuing a campaign of aggressive expansionism for the Midlands kingdom, killing, dismembering and martyred the Christian king Oswald in the battle of Cogwy, (modern day Oswestry?), in 642. Although, like Æthelfrith at Chester, we may question why a Northumbrian king was fighting this far south and west deep in to Welsh-Mercian territory, if the identification of the battle site with Oswestry is correct.
It does seem remarkable that Æthelfrith should have been in a position to penetrate as far as Chester, quite distant from his North-eastern homeland at such an early date. The kingdom of Elmet to the south of Bernicia was still in Celtic hands at this time and had checked Anglian expansion westwards. It has been suggested that Æthelfrith was protecting, or attempting to take control of Anglian settlers between the Pennines and the Irish Sea, but there is little evidence of significant numbers of Anglian settlers in Lancashire this early.  The land west of the Pennines remained in British hands and Anglian settlement between Elmet and Powys at the foot of the Pennines hills in the Peak District did not begin until the middle of the 7th century. The midland kingdom of Mercia, emerging along the upper Trent, was growing in strength although not yet dominant, and if providing refuge to Edwin as discussed above, could therefore be safely assumed to be hostile toward the Northumbrians. It has even been speculated that the battle of Chester was the final defeat of King Cearl of Mercia, overking of most of the Midlands and Wales.  But there is no evidence that Cearl was present at Chester or that he was ever overking of an area of Wales.
We may justifiably suspect Æthelfrith's dynastic ambitions as a reason behind the Battle of the Chester, but Bede does not put any particular emphasis on Edwin's exile being associated with this event, on the contrary, the sources are silent on Æthelfrith demanding Edwin from Chester as he did a year later to Raedwald's court, “he sent messengers to offer that king [Raedwald] a great sum of money to murder him [Edwin], but without effect. He sent a second and a third time, bidding more and more each time, and threatening to make war on him if he refused”. 
Perhaps we find a more sinister motive in the religious aspirations of St Augustine. The Welsh Annals list an important synod of St Augustine with the British bishops at "Urbs Legion" (Chester?) for the year 601 AD. Bede records a second synod in 603 AD:
“In the meantime, Augustine, with the assistance of King Ethelbert, drew together to a conference the bishops, or doctors, of the next province of the Britons, at a place which is to this day called Augustine's Ac, that is, Augustine's Oak, on the borders of the Hwicce and West Saxons; and began by brotherly admonitions to persuade them, that preserving Catholic unity with him, they should undertake the common labour of preaching the Gospel to the Gentiles. For they did not keep Easter Sunday at the proper time, but from the fourteenth to the twentieth moon; which computation is contained in a revolution of eighty-four years.”
“..........The Britons then confessed, that it was the true way of righteousness which Augustine taught; but that they could not depart from their ancient customs without the consent and leave of their people. They therefore desired that a second synod might be appointed, at which more of their number would be present.”
“This being decreed, there came (as is asserted) seven bishops of the Britons, and many most learned men, particularly from their most noble monastery, which, in the English tongue, is called Bancornburg, over which the Abbot Dinooth is said to have presided at that time.”
Augustine required the Britons to comply on three accounts: to keep Easter at the due time; to administer baptism; to preach the word of God to the English nation, then he (the Roman church) would tolerate all the other things although contrary to English customs. The British contingent declared they would not accept any of these conditions or be under his subjection and receive him as their archbishop. Augustine, is then said to have foretold, that if they would not join in unity with their brethren, they should be warred upon by their enemies and if they would not preach the way of life to the English nation, they should perish at their hands and undergo the vengeance of death.
Immediately following this Bede recounts how the English king Æthelfrith raised “a great army against the city of the legions which is called Legacaestir but the English and more correctly Caerlegion by the Britons, and made a great slaughter of that nation of heretics”.  Bede clearly interprets this as divine retribution.
As he was about to give battle Æthelfrith noted that the British had brought their priests, who had come to pray for their side's victory, a large number being from the monastery of Bancornburg (Bangor-is-y-coed) where they was said to be such a great number that it was divided into seven divisions of no less than 300 men each. They had fasted for three days prior to this battle. Bede recalls how Brocmail was appointed as their protector from the “barbarian swords” and defend them whilst they were at prayers. On being informed of the monks role in the battle, Æthelfrith said, "If then they cry to their God against us, in truth, though they do not bear arms, yet they fight against us, because they oppose us by their prayers."
Æthelfrith then commanded the monks to be attacked first, and about twelve hundred of those that came to pray are said to have been killed, only fifty escaped. Brocmail and his men are accused by Bede of turning their back and fleeing at the first approach of the enemy, and left the monks to be slaughtered, thus fulfilling the prediction of Augustine. The result was the complete destruction of the monastery and near total annihilation of its inhabitants, the monks of Bangor.
Onto Part IV: Slaughter of the Saints
1. March Of The Monks Of Bangor by Sir Walter Scott.
2. Rachel Bromwich, Trioedd Ynys Prydein, 2006, University of Wales Press, Third Edition, pp. 52 -58.
3. Bede Book II.
4. Bede Book II. 12.
5. We note a discrepancy here between Bede's dating of the battle and the Welsh account, which suggests the possibility that they may not be accounts of the same battle; Meigen being documented in Welsh sources as being in Cadwallon's homeland.
6. Bede II. 20
7. Bede III. 1
8. D P Kirby, The Earliest English Kings. Revised Edition 2000, Routledge.
9. N J Higham, King Cearl, The Battle of Chester and the Origins of Mercian 'Overkingship.' Midland History 16.
10. Bede Book II. 12
11. Bede Book II. 2
12. Bede Book II. 2
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