In the TV show Vinland Saga, Welsh people in the early 11th century viewed themselves as the continuators of Romano-British culture and heritage ("Britannia"), and some leaders still had Latin names - is this even remotely accurate?

by MadMarx__
y_sengaku

/u/epicyclorama wrote an excellent answer to the similar question as OP before in: Roughly how much Roman influence would be visible in Welsh Culture in Post Anglo-Saxon/Early Medieval Britain? Would people of that time known about the Roman Period?