Although Roman influence in Britain ended before it did in Gaul, Gibbon chooses to place it in the narrative afterwards. You can see why. The situation in Gaul steadily evolved and are developed. It’s very much part of the story of the fall of the Western Empire. What happened in Britain seems to be a very different story indeed, it does feel very much like a footnote to the rest of the book.
The extent of the continuity of institutions in Roman Gaul during and after the barbarian invasions is something that has been widely debated and will no doubt continue to be debated. But in Britain there is no argument. The Romans pulled out and their state was completely destroyed and replaced by invaders from the continent. The tribes were the pagan Saxons, Angles and Jutes. The differences between these three were not great and don’t seem to have translated into any discernable differences in culture on arrival. But they all totally transformed the areas where they settled. The Roman currency disappeared. Christian worship ceased. Almost all the major urban centres were abandoned. Comparing place names in Roman Britain and those of modern England reveals very few examples where the Roman one has survived. London is the only one I can think of. Archeology confirms this brutal transition. There is no pottery in the early Saxon occupation. Even such a basic industry as that did not survive the invasion.
It was supposed by the early historians of Britain– the contemporaries of Gibbon– that the Saxons exterminated the British population in much the way that the English settlers in America were at the time doing to the native Americans. This would account for the total extinction of the language of Roman Britain in England. But Gibbon is a bit less extreme and supposes that large numbers of the natives must have survived, without venturing to put a number on it.
The science of population genetics is still in its infancy, and I expect it will get much more precise in the future. But we can now analyse the DNA of the modern population of Britain. The indications are that about 10% of current English DNA comes from the ingress of the Saxons and the Angles. This only seems a small figure because we tend to think of ourselves as Anglo-Saxons and so expect it to be much higher. Britain has been close to the continent for many centuries and has been in constant genetic contact with it. My guess is that when the data is fully gathered and analysed the figure may well end up lower for the fifth century invasion period. But it will still probably be one of the significant events and probably the most significant in the island’s history.
The exact scale of the Saxon invasion may become clear as a result of DNA evidence, but the exact political situation is always going to be obscure. But the story as Gibbon tells it certainly sounds plausible enough. The island came under the control of a chieftain of uncertain origin called Vortigern. He needed to bolster his authority and did what any Roman emperor would have done confronted with the same situation. He hired some German mercenaries. The package on offer included land to settle. Gibbon is skeptical of the detail in the account where the emissaries of Vortigern have to explain where Britain is to the Saxons. The piratical practices of the Saxons were well established so they would have known all about the rich pickings to be had raiding Roman Britain. The date was 449. The Saxon, or rather the Jutish if that makes any difference, leaders were Hengist and his brother Horsa. The location was Kent. None of these facts can be independently verified. But equally apart from the curious constitutional arrangement of two brothers ruling a tribe simultaneously there is nothing to dispute it either. There is a school of thought that suggests that Hengist and Horsa were actually pagan deities rather than tribal leaders. This isn’t impossible. If we didn’t know that Woden was a God, seeing his name quoted as an ancestor by later Saxon kings might lead us to think that there was an historical man called Woden.
The only trouble with the Hengist and Horsa story, which was the one I learned at school, is that it doesn’t really match the way the Saxon invasion really worked. There must have been multiple attacks backed up by landings across the whole of the English Channel and North Sea coasts. Unlike Gaul where the invaders had kings and political systems that they brought with them from Germany, in what was now to become England there are very few leaders that can be identified. Curiously for someone who became so intimately familiar with the documents of other countries, Gibbon seems to have given the Anglo-Saxon Chronicle a miss as a source – he only refers to it once in a footnote and seems to have derived most of his account of the invasion of Britain from Bede and contemporary historians. It was available in his time in a latin translation so it wasn’t the language that put him off. Maybe he just didn’t have a copy. He refers to a large battle at Anderida but speculates that it might have taken place in Kent. In fact there has never been any doubt of its location at Pevensey on the Sussex coast. The Anglo-Saxon chronicle locates it and names the Saxon commander as Aella, who went on to found the kingdom of Sussex.
The coasts of Kent and Sussex were extensively defended by a string of forts, of which Pevensey was one of the largest. That it was the site of a key battle suggests that this defensive line was held, so the existence of Vortigern or somebody like him co-ordinating resistance to the Saxons is quite believable. But the creation of small states like Kent, Sussex, Wessex and the Isle of White after the conquest imply that the attack was fragmentary. It was also slow and the Britons continually defended themselves for decades and indeed centuries.
But this was probably small scale local stuff. With the exception of the battle of Pevensey, we have no indications of large scale battles. There is a tradition that a British king called Arthur fought ten battles against the Saxon invaders. If this has any truth at all, all it indicates is that there were a lot of different bands of Saxons around available for a ruck. England is small enough that a single mobile unit could travel the length of it and engage with the enemies in a lot of different locations. But it isn’t big enough to support two large armies meeting in full scale battle ten times before the campaign is settled. The stories of King Arthur of course later took on a life of their own, but all the key elements of them are medieval inventions and throw no light at all on this period.
All we can be really sure about is that for the civilised inhabitants of the island the world had collapsed. First the Roman troops had gone. Then contact with the imperial government was lost. Then invaders overran the country taking the farmland, enslaving or killing the inhabitants and imposing their own rules and language. The conquest took over a hundred years to occupy the bulk of what we now call England. This is evidence that the numbers of invaders were not all that great, but also reveals just how much the country had reverted to a primitive state. Where the legions were sophisticated logistical operations that could travel at speed, the Saxon tribes were more like armed gangs.
A Byzantine observer reported the suggestion that the island of Britain was without horses. This can’t possibly be literally true, but might reflect that there were no spare resources to support cavalry forces any longer. King Arthur’s knights might well have fought on foot. Certainly the scale of military operations were such that you could easily keep up without any need to get into a saddle. The founder of the house of Wessex, who was called Cerdic and whose blood is still present in the current British royal family, spent his entire life subduing an area less than the current size of Hampshire. It wasn’t until the time of his grandson Ceaulin that the West Saxons reached the banks of the Severn.
So the Romano-British lost almost everything with the fall of the empire. All that can really be said is that at least they put up a fight, and a long and hard one. And many centuries later it was a British leader that became a legend. There was no continuity with the previous era in England. The Saxons never had a heroic leader like Alaric or Clovis whose name has continued to resonate ever since. But they were the only ones who really totally wiped out all trace of the empire of the Romans.