The English Conquest of Britain
From 'A History of the British Nation' by AD Innes, 1912
Jutes, Angles, and Saxons
In A.D. 410 the Roman legions were withdrawn. In the course of the next century and a half the Jutes, Angles, and Saxons had made themselves masters of the main part of the greater island between the Forth and the Channel, with the exception of the western regions; for in the west the Celtic dominions still stretched in an unbroken line from north to south.
Some years were still to elapse before the west Saxons in the south finally split the Celts of Devon and Cornwall from the Celts of Wales after the battle of Deorham; and it was not till 613 that the Angles of the North severed Wales from Cumbria or Strathclyde after the Battle of Chester. For the most part the history of the conquest is obscure and legendary.
Gildas and Bede
The only record in any sense contemporary is that of the Briton Gildas, about the middle of the sixth century; and he is exceedingly untrustworthy except as concerns what came directly under his own personal cognisance. Otherwise we have to rely on later compilations, a so-called History of the Britons, written about the end of the seventh century, and edited about the beginning of the ninth century by Nennius; the invaluable work of the Venerable Bede, who was born in 673; and the Anglo-Saxon Chronicle, compiled under the auspices of Alfred the Great at the end of the ninth century.
Bede and the Chroniclers did the best they could with their materials; but trustworthy history does not emerge until the closing years of the sixth century, at least as far as details are concerned.
The traditional story is that Roman Britain went to pieces after the withdrawal of the legions, overwhelmed by the incursions of the Picts and Scots. In 449 a southern kinglet, Vortigern, called in to his aid the Jute pirate chieftains Hengist and Horsa, who, having come to rescue, remained to conquer, and were followed by successive swarms of their kinsmen from Denmark, Schleswig, and Holland. The helpless Britons who had forgotten the art of war were exterminated or fled before them; though surprising legends gathered about a British king named Arthur, who, in his time, smote the invaders.
King Arthur is the hero who appears in the History of the Britons, whereas, according to Gildas, the victor who gave a great check to the invaders was Ambrosius Aurelianus. As Gildas himself was probably born before the battle of Mount Badon, the great victory which he attributes to Aurelianus, it may at least be assumed that his statement is tolerably correct. Very little value is to be attached to the History of the Britons, although King Arthur may, on the whole, be accepted as having been a real chief, who performed real deeds of prowess. Still, between Gildas, who represents the Britons in the middle of the sixth century, Bede, who was a careful and critical historian, and the Anglo-Saxon Chronicle, which stands broadly for Bede modified by Wessex tradition, we can arrive at a tolerably consistent account of the Anglo-Saxon Conquest.