It was a good little comment.

Disclaimer, its Halloween and I've had a few and I'm dressed as a skeleton. This may be a little jumbled.

About me: BA Hons Ancient History (mostly Late Roman), 2 x PGDip, Ex History Teacher, Historical Wargamer, reading around a possible PHD. I'm an all round amateur History nerd and armchair general.

I'm going to be using the word "Welsh" and "Wales" a lot. Wales did not exist as a "thing" until relatively recently. By Welsh I mean the collective early kings/ princes (princeps) of Dyfed, Gwynedd, Strathclyde, Cumbia etc etc. and the people who called themselves Bryddoniaid, Cymbrogai. By Wales I mean non-Saxon dominated Post-Roman Britain roughly modern Northern England, Wales and Cornwall. I use the word "petty" for small and "king" for whoever was sitting at the top of the social pile.

The short answer : Read Britannia Prima - Britain's last Roman province by Roger White and then Edward I, A Great And Terrible King by Marc Morris.

Basically the gist is -

The Romans under Count \Comes Theodosius (father of the Emperor) created buffers of militarised tribes on the Northern and Western frontiers of Britain (Cumbria, Strathclyde and Wales) in the late 4th century before Britain was abandoned after a troubling period of raids by Picts and Irish.

Obviously this was to provide a buffer to protect the demilitarised provinces of what is now England. This is where the Welsh myths of founding kings such as Cynedda come from. So by his logic the early kings the West of Britain were placed there by Imperial Authority. Hence the Roman Draco standard as a symbol of authority (which of course is in its modern form the Welsh Flag though it remained such in many cultures for a long time - Saxons, Bretons and Normans all used Draco standards, see the Beaux tapestry) and the importance of lineage inscriptions on standing stones in Wales as statements of Imperial Authority and rights of Kingship through lineage. They are practically the only prominent inscriptions that we have from the post Roman period which kind of emphasises how important tracing your lineage back to a king who ruled by Roman say-so was.

Interesting note that based on the archaeological record of military belt buckles in the post Roman period the Western Romano Britons used Irish foederati and not Saxons. This also points to the different Roman provinces very much "looking to their own defences" independently and not having a common policy of defence.

Anyway, after the Saxons turn up the Western Romano British Civitate states such as that based around Wroxeter heold out for a while against the Saxons (which is where Ambrosius Aurelianus - Arthur Legend comes in) and while they eventually fell the early British kingdoms of Wales and the North of England held on in some form. Obviously eventually Edward I finally had his way with the annexation of Gwynedd which was the last of them.

Another interesting note is the castle Edward built at the former Roman settlement of Caernarfon (anything with a caer in it or chester denotes Roman Ceaster - castle or fort) which is modelled on the walls of Constantinople. Basically by building an "Imperial - Roman" style castle he was stamping his claim on being the new Imperial authority. There is even an "Eagle Tower".

How important was the idea of Romanness to the "Welsh"? Look into the importance of the poem Breuddwyd Macsen Wledig (The Dream of the Emperor Magnus Maximus) which stands alongside the Gododdin and Mabinogion in the Welsh imagination.

TLDR????,

the early Welsh petty kings were put in position by A Roman official and succeeding kings tried to claim authority from this by waving a Draco military standard about and claiming descent from a founding petty king.

To counter the "Nationalist" use of the original statement made by Ward-Perkins It must be remembered that many Welsh kings were also nominal vassals of the English Crown when it suited them. See the book Edward I, A Great And Terrible King by Marc Morris for a good description of the relationship between Llywelyn and Edward.

If you want to look into something really interesting look at how Brittany was settled by a Romano British exodus.