What was so different about Roman and Post Roman Britain?

From modern population studies the English average 38% North Sea Germanic ancestry. The most recent study also points to a substantial post-Roman influx of Iron Age Gaulish-like ancestry, probably via Frankish mediation, not recognised before. 

Ancient DNA studies have shown some Anglo-Saxon settlements to have been composed of 100% Germanic incomers, while others show that native Britons became culturally assimilated to Anglo-Saxon norms and produced children who had hybrid ancestry at a very early date. Men of native ancestry were buried with weapons in the same way as men of Germanic ancestry, there seems to have been little discrimination in these communities based on ancestry.

The Brythonic Celtic names found in the early members of the West Saxon royal family - Cerdic, Ceawlin, Cedda, Caedwalla - show that in some areas native families retained political power and slowly became anglicised. The names of the Mercian kings Pybba, Penda and Peada look far more Celtic than Germanic, perhaps indicating some native British connection for that royal dynasty also. It is notable that the warlike Penda never fought against the British/Welsh, but was always allied to them in wars against the Northumbrians.

This period is, as you may have guessed, one of my 'special interests'.

I've always wondered about the Brythonic names of West Saxon leaders too. I wonder if the Saxons these people were leaders of were foederati, mercenaries paid with land grants and cash in the Roman fashion, it would certainly make sense of the old tales of Kings like Vortigern?

I think it was assimilattion rather than conquest during the earlier period, obviously later it did become violent as Anglo-Saxons took control, we have fairly firm dating evidence for the fall of Romano British towns like Cirencester and Bath.

As for language I wonder how many languages were spoken in Britain at the time? Did we adopt Saxon languages in a sort of rebellion against Rome and Latin? Did the incoming Pagan A/S refuse to use Latin because of it being a religious language?

I think that as we don't really have a specific A/S gene marker it's hard to tell who was who, if we can get Stable Isotopes then we can tell where people grew up, but that dosen't tell us how they came here and thier children would have the stable isotopes of the area they grew up in. A lot of the archaeolgical evidence can be confusing too, is a grave with no grave goods a sign of a Christian or someone at the bottom of society with no possessions, such as a slave? Even were we do have grave goods it can be a confusing picture, were "Germanic" goods fahion, a sign of ancestry, a sign of mixed marriage even? TO give an example, would a future archaeologist wonder if we had been conquered by China and an Empire in South East Asia because so many of our househoid objects come from that area, if there were no documents, how would they know? The picture changes as you move westwards too and in many ways gets more confusing, I've thought for a long time that we should stop thinking about a north/south divide in favour of an east/west one, certainly for pre-industrial revolution stuff.

One of the other things I wonder about is religion at the time, we're told that the Romano-British were Christian, but were they, and what sort of Christianity was it? Also why does there seem to have been no efforts by the Romano-Britons to convert the Anglo-Saxons?  Was thier Christianity more akin to that of the Irish Church with it's differnt dating of easter, different tonsures and abbots instead of bishops, or was it more akin to that of later missionaries such as Augustine?

I would also ask, how widespread Christianity really was in Britain during late antiquity? We know that the empire was officially Christian but how was it in practice? Did other religions still survive in their previous form or did they go underground and become as secretive as Chritians had had to be previously, or was it hybrid?

It's thought by some that Hengist and Horsa the guys who were said to have led the invasion of Britain, were actually the name's of now forgotten gods.

The other thing is that when people think of Britain they tend to think of modern Britain and it's political boundaries, it's shires etc, but that wasn't the case then, there were areas ruled by all sorts of different people, from war lords to petty kings and the remains of Roman civic administration.

Britain deromanised faster and more completely than any other province and given the number of legions based here, was it ever fully Romanised? My feeling is that it wasn't, hence why we see a return to pre-Roman territiorial boundaries, the reoccupation of hillforts and it would seem any real will or wish to go back to being part of the empire?

I've always wondered about the Brythonic names of West Saxon leaders too. I wonder if the Saxons these people were leaders of were foederati, mercenaries paid with land grants and cash in the Roman fashion, it would certainly make sense of the old tales of Kings like Vortigern?

I think it was assimilattion rather than conquest during the earlier period, obviously later it did become violent as Anglo-Saxons took control, we have fairly firm dating evidence for the fall of Romano British towns like Cirencester and Bath.

As for language I wonder how many languages were spoken in Britain at the time? Did we adopt Saxon languages in a sort of rebellion against Rome and Latin? Did the incoming Pagan A/S refuse to use Latin because of it being a religious language?

I think that as we don't really have a specific A/S gene marker it's hard to tell who was who, if we can get Stable Isotopes then we can tell where people grew up, but that dosen't tell us how they came here and thier children would have the stable isotopes of the area they grew up in. A lot of the archaeolgical evidence can be confusing too, is a grave with no grave goods a sign of a Christian or someone at the bottom of society with no possessions, such as a slave? Even were we do have grave goods it can be a confusing picture, were "Germanic" goods fahion, a sign of ancestry, a sign of mixed marriage even? TO give an example, would a future archaeologist wonder if we had been conquered by China and an Empire in South East Asia because so many of our househoid objects come from that area, if there were no documents, how would they know? The picture changes as you move westwards too and in many ways gets more confusing, I've thought for a long time that we should stop thinking about a north/south divide in favour of an east/west one, certainly for pre-industrial revolution stuff.

One of the other things I wonder about is religion at the time, we're told that the Romano-British were Christian, but were they, and what sort of Christianity was it? Also why does there seem to have been no efforts by the Romano-Britons to convert the Anglo-Saxons?  Was thier Christianity more akin to that of the Irish Church with it's differnt dating of easter, different tonsures and abbots instead of bishops, or was it more akin to that of later missionaries such as Augustine?

I would also ask, how widespread Christianity really was in Britain during late antiquity? We know that the empire was officially Christian but how was it in practice? Did other religions still survive in their previous form or did they go underground and become as secretive as Chritians had had to be previously, or was it hybrid?

It's thought by some that Hengist and Horsa the guys who were said to have led the invasion of Britain, were actually the name's of now forgotten gods.

The other thing is that when people think of Britain they tend to think of modern Britain and it's political boundaries, it's shires etc, but that wasn't the case then, there were areas ruled by all sorts of different people, from war lords to petty kings and the remains of Roman civic administration.

Britain deromanised faster and more completely than any other province and given the number of legions based here, was it ever fully Romanised? My feeling is that it wasn't, hence why we see a return to pre-Roman territiorial boundaries, the reoccupation of hillforts and it would seem any real will or wish to go back to being part of the empire?

Oohh Pelagius, now there's fascinating or I've always found his ideas to be anyway. What made it into mainstream Christianity and what didn't is a subject of ongoing fascination to me. I think a lot of the Christian world had different ideas about Christianity was, just think of the biggest split between Rome and Greek Orthodox, then you've got all the North African branches such as Copts, they all had and have slightly different ways of doing things.

I've heard it said that Marianism started in the German territories because they couldn't accept the lack of the Divine Feminine, I doubt if this were true that they would be the only ones uncomfortable with only a Divine Masculine. It would seem that Isis was one of the most widely worshiped Goddesses in the late Roman world as she shared many aspects with the North European Goddess Freya, I think incorporating the Divine Feminine, in the form of Mary would be needed to attract more converts to a wholey Christianised worship.

If we had large numbers of Germanic foederati then I imagine that the local populace would of learnt at least a smattering of thier dialects.

It's quite surprising how many attempted usurpations were launched from Britain, noone fo them seem to have been successfull, but there does seem to have been something about Britain that bred rebellions, not just amoung locals but incomming administrators and troops.

I've had my ancestral DNA done and that came back as 87% southern English, 7% Iberian, which I've not been able trace at all over the last couple of hundred years and the rest are Northern European I would like to have it done again and in more depth with my haplotypes done too. I was surprised to have no Scottish, Scandinavian or Irish. It all makes me wonder just how long my ancestry is in this country? One branch seems to have barely moved from Sussex/Kent and another from West Sussex/Hampshire/Berkshire and Wiltshire and some of that seems to have been due to changes in county boundaries rather than movements of people. It all makes me think that we've been here for a long time and probably have been farm labourers for generations. Do you know of any reliable testing companies? I'm a bit dubious of the ancestry type ones, they seem to rejig their values a bit to often for my comfort.

Nordic Bronze Age is pretty cool though.

I have a friend who is a professor specialising in the study of ancient and population DNA. He has contributed to a number of papers on the Anglo-Saxon 'adventus'. I am persuaded that the techniques now available can discriminate between the genomes of the Iron Age British, Iron Age Gaulish and 'North Sea Germanic' (the coastal peoples from the Netherlands to Jutland). Being an avowed Celticist, I was slightly disappointed in finding that my Y chromosome originated in Southern Scandinavia in the Nordic Bronze Age. Therefore, my paternal line came over to Britain either with the Anglo-Saxons or the Vikings. However, I have a lot of recent Irish ancestry, enough to satisfy my cravings for all things Celtic.

Hengist means 'stallion' and Horsa means 'horse', which sounds a bit fishy as being the given names of human beings.

Pelagius was a Late Roman British bishop who pedalled ideas about Free Will that ran in opposition to those of St Augustine of Hippo. Pelagianism was eventually declared heretical, so I imagine that Britain had a lot of Christians that the rest of the Roman world considered heretics. Another reason for Britain to break away from the Empire. 

There is an idea that bilingual people assimilate a third language far more easily than monoglots. Large numbers of people in lowland Britain may have been bilingual in Latin and Common Brythonic before the arrival of the Anglo-Saxons, this may have contributed to the speedy adoption of the newcomers' language.