This is an excerpt from Simon Stirling’s The Grail, which I reviewed here – https://druidlife.wordpress.com/2018/04/29/the-grail-relic-of-an-ancient-religion-a-review/
The Annals of Tigernach list four battles for the year 594:
The battle of Ratha in Druadh & the battle of Áird Sendoim. The slaying of the sons of Áedán i.e. Bran & Domangart & Eochaid Find & Artúr, in the battle of Circhenn, in which Áedán was the victor, & the battle of Corann.
The first two battles were closely linked, the battle of Áird Sendoim (‘The Headland’, near Peterhead, ‘on the coast of Mordei’) being immediately followed by Arthur’s ‘Unrestrained Ravaging’ of Morgan’s Tillymorgan hill-fort. The Annals of Ulster described this as the ‘battle of Ràth in druaid’ (Early Irish ràth, a ‘residence surrounded by an earthen rampart’). It took place in the ‘Sorcerer’s land’ (Early Irish drui – a ‘Druid’; genitive druad). Morgan was considered ‘skilful’ (medrod) by the Britons, which would imply some level of Druidic knowhow – including, no doubt, the art of raising a ‘ghost fence’, such as that which Geraint fatally crossed above the sands of Cruden Bay.
The Arthurian legend of Culhwch and Olwen recalls that ‘when Arthur had landed in the country’ in pursuit of the fearsome king-turned-boar, Twrch Trwyth, ‘there came unto him the saints of Ireland and besought his protection.’ There were Irish monks at Old Deer, just west of Peterhead. Arthur then went ‘as far as Esgeir Oerfel’ – the ‘Cold Ridge’ of the Grampians – ‘where the Boar Trwyth was with his seven young pigs.’
There followed three days of fighting, after which Arthur sent in his interpreter to parley. Morgan’s spokesman vowed that he would yield nothing to Arthur: ‘“And tomorrow morning we will rise up hence, and we will go into Arthur’s country, and there we will do all the mischief that we can.”’
Morgan escaped with Gwenhwyfar, quite possibly in the Chariot of Morgan the Wealthy (Car Morgan Mwynfawr), which became one of the Thirteen Treasures of Britain: ‘if a man went in it, he might wish to be wherever he would, and he would be there quickly.’ Arthur, meanwhile, sought to block the arrival of any hostile reinforcements from his half-brother’s Highland kingdom.
The evidence for this move on Arthur’s part is the presence of an Arthur’s Seat (Suiarthour in 1638; now it is just Suie) at the head of Glen Livet. This was the channel, on the eastern edge of the Highlands, through which Gartnait’s warriors might have hastened to Morgan’s defence.
What happened next was hinted at by Myrddin:
I predict a summer of fury,
Contention of brothers,
Treachery out of Gwynedd:
The lofty exile and the good-pledge [i.e. ‘hostage’],
The tall one [Gwenhwyfar] from the land of Gwynedd.
Seven hundred-ships from Saxon-land,
Blown north by the wind;
And in Aberdeen they confer.
Morgan’s ‘Saxon’ allies – the Angles of Northumbria – sent seven ships, each carrying 100 men, to supplement his Miathi spears (Geoffrey of Monmouth later bumped this up to ‘eight hundred ships’). Arthur almost certainly spied these reinforcements from the hill of Bennachie in Aberdeenshire (an Arthur’s Cairn – Arthouriscairne – was recorded there in 1595), having paused at Percylieu (perc-y-llew, the ‘Lion’s Perch’; rendered as ‘Preseleu’ in the Culhwch and Olwen legend) en route to the coast.
The Gododdin were with Arthur, meaning that Lothian was barely defended. Morgan and his supporters saw their opportunity to race south and seize Manau (Stirling) and the Edinburgh capital of Lothian.
The tale of Culhwch and Olwen recounts the bloody pursuit of the Boar-King from the ‘Cold Ridge’ towards the ‘Vale of Manau’ (Dyffryn Amanw). Morgan’s spokesman had sworn that they would ‘go into Arthur’s country’ and there do ‘all the mischief that we can.’ And so Morgan, with his Saxons and his Picts, made for the crucial bulwark of Manau Gododdin.
Arthur and his battered war-band followed them into Angus.
Find out more about the book here – http://www.moon-books.net/books/grail