1. History. - The history of Britain after the withdrawal of the Roman troops is extremely obscure, but there can be little doubt that for many years the inhabitants of the provinces were exposed to devastating raids by the Picts and Scots. According to Gildas it was for protection against these incursions that the Britons decided to call in the Saxons. Their allies soon obtained a decisive victory; but subsequently they turned their arms against the Britons themselves, alleging that they had not received sufficient payment for their services. A somewhat different account, probably of English origin, may be traced in the Historia Brittonum, according to which the first leaders of the Saxons, Hengest and Horsa, came as exiles, seeking the protection of the British king, Vortigern. Having embraced his service they quickly succeeded in expelling the northern invaders. Eventually, however, they overcame the Britons through treachery, by inducing the king to allow them to send for large bodies of their own countrymen. It was to these adventurers, according to tradition, that the kingdom of Kent owed its origin.
The story is in itself by no means improbable, while the dates assigned to the first invasion by various Welsh, Gaulish and English authorities, with one exception all fall within about a quarter of a century, viz. between the year 428 and the joint reign of Martian and Valentinian III. (450-455).
For the subsequent course of the invasion our information is of the most meagre and unsatisfactory character. According to the Anglo-Saxon Chronicle the kingdom of Sussex was founded by a certain Ella or aelle, who landed in 477, while Wessex owed its origin to Cerdic, who arrived some eighteen years later. No value, however, can be attached to these dates; indeed, in the latter case the story itself is open to suspicion on several grounds (see Wessex). For the movements which led to the foundation of the more northern kingdoms we have no evidence worth consideration, nor do we know even approximately when they took place. But the view that the invasion was effected throughout by small bodies of adventurers acting independently of one another, and that each of the various kingdoms owes its origin to a separate enterprise, has little probability in its favour. Bede states that the invaders belonged to three different nations, Kent and southern Hampshire being occupied by Jutes (q.v.), while Essex, Sussex and Wessex were founded by the Saxons, and the remaining kingdoms by the Angli (q.v.). The peculiarities of social organization in Kent certainly tend to show that this kingdom had a different origin from the rest; but the evidence for the distinction between the Saxons and the Angli is of a much less satisfactory character (see Anglo-Saxons). The royal family of Essex may really have been of Saxon origin (see Essex), but on the other hand the West Saxon royal family claimed to be of the same stock as that of Bernicia, and their connexions in the past seem to have lain with the Angli.
We need not doubt that the first invasion was followed by a long period of warfare between the natives and the invaders, in which the latter gradually strengthened their hold on the conquered territories. It is very probable that by the end of the 5th century all the eastern part of Britain, at least as far as the Humber, was in their hands. The first important check was received at the siege of "Mons Badonicus" in the year 517 (Ann. Cambr.), or perhaps rather some fifteen or twenty years earlier. According to Gildas this event was followed by a period of peace for at least forty-four years. In the latter part of the 6th century, however, the territories occupied by the invaders seem to have been greatly extended. In the south the West Saxons are said to have conquered first Wiltshire and then all the upper part of the Thames valley, together with the country beyond as far as the Severn. The northern frontier also seems to have been pushed considerably farther forward, perhaps into what is now Scotland, and it is very probable that the basin of the Trent, together with the central districts between the Trent and the Thames, was conquered about the same time, though of this we have no record.
Again, the destruction of Chester about 615 was soon followed by the overthrow of the British kingdom of Elmet in south-west Yorkshire, and the occupation of Shropshire and the Lothians took place perhaps about the same period, that of Herefordshire probably somewhat later. In the south, Somerset is said to have been conquered by the West Saxons shortly after the middle of the 7th century. Dorset had probably been acquired by them before this time, while part of Devon seems to have come into their hands soon afterwards.
The area thus conquered was occupied by a number of separate kingdoms, each with a royal family of its own. The districts north of the Humber contained two kingdoms, Bernicia (q.v.) and Deira (q.v.), which were eventually united in Northumbria. South of the Humber, Lindsey seems to have had a dynasty of its own, though in historical times it was apparently always subject to the kings of Northumbria or Mercia. The upper basin of the Trent formed the nucleus of the kingdom of Mercia (q.v.), while farther down the east coast was the kingdom of East Anglia (q.v.). Between these two lay a territory called Middle Anglia, which is sometimes described as a kingdom, though we do not know whether it ever had a separate dynasty. Essex, Kent and Sussex (see articles on these kingdoms) preserve the names of ancient kingdoms, while the old diocese of Worcester grew out of the kingdom of the Hwicce (q.v.), with which it probably coincided in area. The south of England, between Sussex and "West Wales" (eventually reduced to Cornwall), was occupied by Wessex, which originally also possessed some territory to the north of the Thames. Lastly, even the Isle of Wight appears to have had a dynasty of its own. But it must not be supposed that all these kingdoms were always, or even normally, independent.