This period has attracted a great deal of academic and popular debate, in part because of the scarcity of the source material, and in part because historians argue that the events - in terms of invasion, settlement and resettlement - that took place within this particular time forged the beginnings of the national identities that would prevail within the British Isles over the coming centuries. The term Post-Roman Britain is also used for the period, mainly in non-archaeological contexts. 'Sub-Roman' and 'post-Roman' are both terms that apply to the old Roman province of Britannia, that is Britain south of the Forth-Clyde line. The history of control of the area between Hadrian's Wall and the Forth-Clyde line is unclear. North of the line was an area inhabited by tribes about whom so little is known that we resort to calling them by a generic name: Picts.
The term Late Antiquity, implying wider horizons, is finding more use in the academic community, especially when transformations of classical culture common throughout the post-Roman West are examined; it is less successfully applied to Britain at the time. The period may also be considered as part of the Early Middle Ages, if continuity with the following periods is stressed. A range of more dramatic names are given to the period in popular (and some academic) works: the Dark Ages, the Brythonic Age, the Age of Tyrants, or the Age of Arthur.
There is very little extant written material available from this period, though there is a considerable amount from later periods that may be relevant. A lot of it deals with the first few decades of the fifth century only. The sources can usefully be classified into British and continental, and into contemporary and non-contemporary.
Two primary contemporary British sources exist: the Confessio of Saint Patrick and Gildas' De Excidio Britanniae ("On The Ruin Of Britain").. Gildas is the nearest to a source of Sub-Roman history but there are many problems in using it. The document represents British history as he and his audience understood it. Though a few other documents of the period do exist they are not directly relevant to British history, such as Gildas' letters on monasticsm. Patrick's Confessio reveals aspects of life in Britain, from whence he was abducted to Ireland. It is particularly useful in highlighting the state of Christianity at the time. Gildas' De Excidio Britanniae is a jeremiad; it is written as a polemic to warn contemporary rulers against sin, demonstrating through historical and biblical examples that bad rulers are always punished by God - in the case of Britain, through the destructive wrath of the Saxon invaders. The historical section of De Excidio is short, and the material in it is clearly selected with Gildas' purpose in mind. There are no absolute dates given, and some of the details, such as those regarding the Hadrian and Antonine Walls are clearly wrong. Nevertheless, Gildas does provide us with an insight into some of the kingdoms that existed when he was writing, and to how an educated monk perceived the situation that had developed between the Anglo-Saxons and the Britons.
There are more continental contemporary sources that mention Britain, though these are highly problematic. The most famous is the so-called Rescript of Honorius, in which the Western Emperor Honorius tells the British civitates to look to their own defence. The first reference to this rescript is written by the sixth-century Byzantine scholar Zosimus and is located randomly in the middle of a discussion of southern Italy; no further mention of Britain is made, which has led some, though not all, modern academics to suggest that the rescript does not apply to Britain, but to Bruttium in Italy. The Gallic Chronicle (441 and 511) says prematurely that "Britain, abandoned by the Romans, passed in to the power of the Saxons" and provides information about St Germanus and his visit(s) to Britain, though again this text has received considerable academic deconstruction. The work of Procopius, another sixth-century Byzantine writer, makes some references to Britain though the accuracy of these is uncertain.
There are numerous later written sources that claim to provide accurate accounts of the period. The first to attempt this was the monk Bede, writing in the early 8th century. He based his account of the Sub-Roman period in his Historia ecclesiastica gentis Anglorum (c.731) heavily on Gildas, though he tried to provide dates for the events Gildas describes. It was written from an anti-Briton point of view. Later sources, such as the Historia Brittonum often attributed to Nennius, the Anglo-Saxon Chronicle (again written from a non-Briton point of view, based on West Saxon sources) and the Annales Cambriae are all heavily shrouded in myth and can only be used as evidence for this period with caution. There are also documents giving Welsh poetry (of Taliesin and Aneirin) and land deeds (Llandaff charters) that appear to date back to the 6th century.
After the Norman Conquest there were many books written that purport to give the history of the Sub-Roman Period. These have been influenced by the fictionalised account in Geoffrey of Monmouth's "History of the Kings of Britain". Therefore they can only be regarded as showing how the legends grew. Not until modern times have serious studies of the period been undertaken.
Archaeology provides further evidence for this period, though of a different nature than that provided by documents. In the Sub-Roman period there seems to have been a preference for using less durable materials than in the Roman period. However, brooches, pottery and weapons from this period have survived. The study of burials and cremations, and the grave goods associated with these, has done much to expand the understanding of cultural identities in the period. Archaeology has shown the continuity with Roman education, trade with the Mediterranean and with Celtic art.
Excavations of settlements have revealed how social structures might have been changing, and the extent to which life in Britain continued unaltered in certain aspects into the early medieval period. Excavations have taken place on hilltops, the so-called "Hillforts", towns and monasteries. Work on towns has been particularly important in this respect. Work on the hill-forts has shown evidence of refurbishment in this period as well as evidence of overseas trade. One of the earliest major excavations was at Tintagel (Radford 1939). Rectangular structures were uncovered which were interpreted as a monastery together with much Mediterranean pottery. Later re-interpretation suggests that it was a princely stronghold and trading post. Another important excavation was at Dinas Powys (Alcock 1963) which showed evidence of metalworking. Alcock also led the excavations at South Cadbury (Alcock 1995). Many other sites have now been shown to have been occupied during the Sub-Roman period, including Birdoswald and Saxon Shore forts. Excavations in many towns have shown signs of occupation, particularly Wroxeter. "Sunken Featured Buildings" are associated with the Saxons and occur in some Roman towns.
Work on field systems and environmental archaeology has also highlighted the extent to which agricultural practice continued and changed over the period. Archaeology, however, has its limits, especially in dating. Although radio-carbon dating can provide a rough estimate, this is not accurate enough to associate archaeological finds with historical events. Dendrochronology is accurate enough to do this, though few suitable pieces of wood have been uncovered. Coins would normally prove the most useful tool for dating, though this is not the case for sub-Roman Britain since no newly-minted coins are believed to have entered circulation after the very early fifth century.
There is some archaeological evidence for Anglo-Saxons and Britons living on the same site. For example, in the cemetery at Wasperton, Warwickshire, it is possible to see one family adopting Anglo-Saxon culture over a long period.
At the start of the 5th century Britannia formed part of the Western Roman Empire under Honorius However, signs of decline were already appearing and some Saxons may already have been in England as mercenaries. Roman troops were withdrawn by Stilicho in 402 and bulk coin payments ceased around this time. In 406 the army in Britain revolted, electing three successive "tyrants" the last of which took troops to the continent. He became a joint emperor as Constantine III but was defeated and subsequently executed in 411. Meanwhile there were barbarian raids on Britain in 408 but these seem to have been defeated. After 410 Honorious apparently sent letters to the cities of Britain telling them to fend for themselves, though this is sometimes disputed. Later civil wars seem to have broken out, which have been interpreted either as being between pro-Roman and independence groups or between "Established Church" and Pelagian parties (Myres 1965, Morris 1965), a class struggle between peasants and land owners (Thompson 1977, Wood 1984) and a coup by an urban elite (Snyder 1988). However, mostly life seems to have continued as before in the countryside and on a reduced scale in the towns as evidenced by the descriptions of Saint Germanus' visits. Feuding kingships replaced the centrally governed Roman provinces.
Gildas says that a "council" was convened by Vortigen to find ways of countering the barbarian threat, which opted to hire Saxon mercenaries following Roman practise. After a while these turned against the British and plundered the towns. A British leader Ambrosius Aurelianus fought against them, in a number of battles apparently over a long period. Towards the end of this period there was the Battle of Mons Badonicus, around AD 500, which later sources claimed was won by King Arthur though Gildas does not identify him. Subsequent to this there was a long period of peace. The British seem to have been in control of England and Wales roughly west of a line from York to Bournemouth. The Saxons had control of Northumberland as well as East Anglia and South East England.
Writing in Latin perhaps about AD 540, Gildas gives a preliminary account of the History of Britain but the earlier part is in error. He castigates five rulers in western Britain - Constantine of Dumnonia, Aurelius Caninus, Vortipor of the Demetae, Cuneglassus and Maglocunus - for their sins. He also attacks the British clergy. He gives information on the British diet, dress and entertainment. He writes that Britons were killed, emigrated or were enslaved but gives no idea of numbers of each type.
In the late 6th century there was another period of Saxon expansion, starting with the capture by Wessex of Sarum in AD 552 and including entry into the Cotswolds area after the Battle of Deorham, though the accuracy of the entries in the Anglo-Saxon Chronicles for this period has been questioned. This activity seems to have separated the Britons of the South West England (known later as the West Welsh) from those of Wales. (Just after the period being discussed, the Battle of Chester seems to have separated the latter from those of the north of England.) At the end of this period of British history the Britons were still in control of about half of England and Wales.
There were also areas that became Saxon kingdoms:-
In AD 429 a British Deacon Palladius had requested support from the Pope in Rome to combat Pelagianism. Bishops Germanus and Lupus of Troyes were sent. During this time it is alleged that Germanus, a former military commander, led the British to the "Halelujah" victory, possibly in Wales. Germanus is said to have made a second visit to England later.
In the north Whitehorn is said to be the earliest church in Scotland, being founded in the 5th century by St Ninian. Corotius (or Ceretic) was a Christian king who was the recipient of the letter from St. Patrick. His base was Dumbarton Rock in Strathclyde and his descendant Riderch Hael is named in the "Life of St Columbus". Riderch was a contemporary of Aedan mac Gabrain of Dal Riata and Urien of Rheged, as well as of Aethelfrith of Bernicia. Unlike St Columba, Kentigern the supposed apostle to the Britons of the Clyde, and alleged founder of Glasgow, is a shadowy figure.
Similarly, studies of placenames give clues about the linguistic history of an area. England (except Cornwall) shows little evidence now of Celtic in its placenames. There are scattered Celtic placenames throughout, increasing towards the west. There are also Celtic river names and topographical names. The place-name and linguistic evidence has been explained by saying that the settlement of Anglo-Saxons, being politically and socially dominant in the south and east of Britain, meant that their language and culture also became dominant. Names with a Latin element suggest continuity of settlement, while some place names have names of pagan German deities. Names of British origin are usually taken as indicating survival of a British population, though this may not be so. Names based on the Anglo-Saxon word for the British, wealh, are also taken as indicating British survival. One possible indication of British survival was the remnant of a Bythonic derived numeric system that was used by shepherds for counting sheep. This remained in use up to the early 20th C., in parts of Northern and Central England. (see Yan Tan Tethera).
Epigraphic evidence from surviving inscriptions on stones provide another source of information on the settlements of Britons and "Saxons" in this period. Celtic inscribed stones occur in western England and Wales that relate to this period and the CISP project has been set up to record these and provide information online. In the northwest the inscriptions are written in runes and provide information on the settlement of Angles. (Inscriptions in northern Scotland are in ogham, some in an unknown language.)
Germanic dialects replaced Latin or Celtic in the eastern part of England.
Fresh interpretation of the above genetic evidence by Stephen Oppenheimer in The Origins of the British: A Genetic Detective Story and new DNA sampling (Y-chromosome and mtDNA) by Bryan Sykes for his book Blood of the Isles suggest that the contribution of Anglo-Saxons and other late invaders to the British gene pool may have been very limited, and that the majority of English people (about two-thirds) and British people (about three-quarters) descend from palæolithic settlers that migrated from the western European Ice Age refuge, this observation may support the idea of an ancient relationship between the populations of the Atlantic façade of Europe, though the eastern and south eastern coasts of Great Britain do not belong to this zone. Sykes and Oppenheimer claim that even in the east of England, where there is the best evidence for migration, no more than 10% of paternal lines may be designated as coming from an “Anglo-Saxon” migration event and that in the same English regions 69% of male lines are still of aboriginal origin. Stephen Oppenheimer instead postulates a possible pre-Anglo-Saxon genetic relationship between the modern populations of England (especially the south and east) and the people living on the opposing North Sea regions, indicating a much older pre-Roman Germanic influence in south and east England. There is some evidence that Y chromosome Haplogroup I, which occurs at similar frequencies around the North Sea coast may represent a mesolithic colonisation rather than an Anglo-Saxon migration as is contested by other researchers. This haplogroup represents a migration from the Balkan refuge that may have travelled along inland European rivers rather than by the Atlantic coast.
Oppenheimer also postulates that the arrival of Germanic languages in England may be considerably earlier than previously thought, and that both mainland and English Belgae (from Gaul) may have been Germanic-speaking peoples and represented closely related ethnic groups (or a single cross channel ethnic group).
The traditional view has been deconstructed to a considerable extent since the 1990s. At the centre of this is a re-estimation of the numbers of Anglo-Saxons arriving in Britain during this period. A lower figure is now generally accepted, making it highly unlikely that the existing British population was substantially displaced by the Anglo-Saxons. The Saxons are thus seen as a ruling elite with acculturisation of the local population. Thus "Saxon" graves may be of Britons.
There is some controversy as to why Roman rule ended in Britain. The view first advocated by Mommsen was that Rome left Britain. This argument was substantiated over time, most recently by A.S. Esmonde-Cleary. According to this argument, internal turmoil in the Roman Empire and the need to withdraw troops to fight off barbarian armies led Rome to abandon Britain. It was the collapse of the imperial system that led to the end of imperial rule in Britain. However, Michael Jones has advanced an alternative thesis that argues that Rome did not leave Britain, but that Britain left Rome. He highlights the numerous usurpers who came from Britain in the late fourth and early fifth century, and that a supply of coinage to Britain had dried up by the early fifth century, meaning administrators and troops were not getting paid. All of this, he argues, led the British people to rebel against Rome. Both of these arguments are open to criticism, though as yet no further developments have been made in understanding why the end of Roman Britain occurred. ''' However, the violent nature of the period should not be overlooked, and it is likely that this period was a time of endemic tension, alluded to in all of the written sources. This may have led to the deaths of a substantial number of the British population. There are also references to plagues. The evidence from land use suggests a decline in production, which might be a sign of population decline.
It is clear that some British people migrated to the continent, which resulted in the region of Armorica in northwest Gaul becoming known as Brittany. There is also evidence of British migration to Gallaecia, in Hispania. The dating of these migrations is uncertain, but recent studies suggest that the migration from southwestern Britain to Brittany may have begun as early as AD 300 and was largely ended by 500. These settlers, unlikely to be refugees if the date was this early, made their presence felt in the naming of the westernmost, Atlantic-facing provinces of Armorica, Kerne/Cornouaille ("Kernow/Cornwall") and Domnonea ("Devon"). However, there is clear linguistic evidence for close contacts between the southwest of Britain and Brittany across the sub-Roman period.
In Galicia, in the northwest corner of the Iberian peninsula, another region of traditional Celtic culture, the Suebian Parochiale, drawn up about 580, includes a list of the principal churches of each diocese in the metropolitanate of Braga (the ecclesia Britonensis, now Bretoña), which was the seat of a bishop who ministered to the spiritual needs of the British immigrants to northwestern Spain: in 572 its bishop, Mailoc, had a Celtic name.. The settlers had brought their Celtic Christianity with them but finally accepted the Latin Rite at the Council of Toledo in 633. The diocese stretched from Ferrol to the Eo River. In Spain, the area has sometimes been dubbed "the third Britain" or "the last Britain".
Non-Anglo-Saxon kingdoms began appearing in western Britain, which are first referred to in Gildas's De Excidio Britanniae. To an extent these kingdoms may have derived from Roman structures. However, it is also clear that they drew on a strong influence from Hibernia, which was never part of the Roman Empire. Archaeology has helped further the study of these kingdoms, notably at sites like Tintagel or the South Cadbury hill-fort.
In the north there developed the British kingdoms of the Hen Ogledd, the "Old North", comprising Ebrauc (probable name), Bryneich, Rheged, Strathclyde, Elmet and Gododdin. Fifth and sixth century repairs along Hadrian's Wall have been uncovered, and at Whithorn in southwestern Scotland (possibly the site of St Ninian's monastery). Chance discoveries have helped document the continuing urban occupation of some Roman towns such as Wroxeter and Caerwent. Continued urban use might be associated with an ecclesiastical structure.
Western Britain has attracted those archaeologists who wish to place King Arthur as a historical figure. Though there is little contemporary written evidence for this, and archaeological evidence does suggest a possibility that a Romano-British king might have wielded considerable power during the sub-Roman period, as demonstrated by the creation of sites such as Tintagel and earthworks such as the Wansdyke. Such interpretations continue to attract the popular imagination and the scepticism of academics.
While pushed back politically and linguistically, British scholars and ecclesiastics had a significant impact on the Anglo-Saxon newcomers through literacy, ecclesiastical social constructs and historical memory of the Roman period in Britain, particularly after the Christianizing of the Anglo-Saxons by Augustine. Coming from a fully oral cultural background the Anglo-Saxons were heavily influenced by the more developed Christianized and literate culture of the Britons. British scholars were often employed at Anglo-Saxon courts to assist in the management of the kingdoms. Through this process, British culture was re-introduced to those parts of Britain lost to the British politically. The epitome of this process is the adoption of the legendary British war leader, King Arthur, as the national hero of the English, due to the literary work of Welsh historians.
According to a new study, an apartheid-like system existed in early Anglo-Saxon England, which prevented the native British genes getting into the Anglo-Saxon population by restricting intermarriage and wiped out a majority of original British genes in favour of Germanic ones. According to research led by University College London, Anglo-Saxon settlers enjoyed a substantial social and economic advantage over the native Celtic Britons who lived in what is now England, for more than 300 years from the middle of the 5th century.
Stephen Oppenheimer maintains that all invasions since the Romans have had very little impact upon the gene pool of the British Isles, and that its inhabitants nearly all belong to the same genetic group as the original prehistoric inhabitants of the Isles. He says that most people on the Isles are genetically similar to the Basque peoples of northern Spain, from 90% in Wales to 66% in East Anglia (named after the Germanic Anglo-Saxons, in England. Archaeologists have uncovered Celtic artifacts in England dating from later times than the supposed Anglo-Saxon 'apartheid' of Britons was believed to take place. Areas around the Pennines still retained a strong Celtic culture, a prime example being the speaking of the Cumbric language until late into the 12th century, and the Cornish language even longer, until the 18th century. Celtic traditions and words have survived even until today, such as Cornish, Cumbrian and Lancashire wrestling, the Northumbrian smallpipes and many placenames (such as Pen-y-Ghent in Yorkshire). The influx of Irish immigrants into English cities such as Manchester (where 35% of the population are believed to be of Irish descent), during the Irish Diaspora, could be seen as a reversal of the displacement of Celtic peoples from England.