The Core Battles of Arthur Dux Bellorum in Flavia Caesariensis
by Dane Pestano

https://darkagehistory.blogspot.com/2014/12/the-campaigns-of-arthur-dux-bellorum-in.html
The Saxons had arrived in Britain as federates in around 465 according to Gildas and had broken out of their settlements in the east to pillage the towns along the Roman road systems in the early 470's. We know from Gildas that St Albans (Verulamium) was one of these towns in Flavia Caesariensis and the other Chester at opposite ends of the of the territory (It was thought this may have been Caerleon, Newport, South Wales, in Secunda, but see later below) . Gildas in effect was telling us where the extent of the troubles was. Ambrosius had begun the fightback in the mid 470's and must have managed to pacify south eastern Flavia Caesariensis in his campaigns as none of Arthur's battles are in this part, ie north east of the Thames to the Ouse in East Anglia. Britannia Prima, the whole region south of the Thames may have escaped any major troubles, perhaps only Kent being problematical although this area may in fact have been more Frankish, rather than Saxon in our period as the archaeology indicates. The following map shows the early perceived Saxon cemeteries in Britain reflecting where they lived and you can see from this that they were mainly billeted in Flavia Caesariensis and I have added the probable rebellion routes.