Britannia (England and Wales) had been a Roman province since 43 CE. Roman soldiers - many of them auxiliaries - had settled in cities and Xianity was
apparently widespread. By the fourth century, with the Empire in increasing disarray and preoccupied with fighting off threats closer to both Rome and
Byzantium, the Romano-British were feeling inadequately defended. Roman troops were withdrawn in 402, leaving only the standing army, who revolted in 406,
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 the Romano-British apparently successfully repelled a Saxon incursion in 408. In 409 either they or the Bretons
expelled the civilian Roman governor. In 410 the Emperor Honorius turned down appeals for help, apparently against a peasant revolt against landowners.
With the higher levels of the military and civil government gone, local authorities had to manage their own affairs, and the country slowly turned into
a patchwork of local warlords' fiefdoms, although all aspired to Roman degrees of orderliness and culture.
There are only fragmentary contemporary accounts. As first Gildas in the early 6th century in his De Excidio et Conquestu Britanniae ("On the Ruin and
Conquest of Britain") and then Bede in about 731 in his Historia Ecclesiastica Gentis Anglorum ("Ecclesiastical History of the English People") told the
story, the warlord Vortigern invited the Saxons to assist him against his enemies and in exchange gave them land in the east, but they brought over their
entire tribe and settled England from sea to sea. Bede gives a date, 446, but it is likely based on guesswork. He also says there were actually three
tribes: Angles, Saxons, and Jutes. And he names the leaders: the suspiciously cultic-named brothers Hengest and Horsa ("stallion" and "horse").
Academics now scoff at this story and regard the Anglo-Saxon settlement as a more or less gradual affair not prompted by an invitation. Many have also cast
doubt on the notion of three separate tribes, for which Bede is the only source. From placename evidence, what seems to have happened is that Saxons first
moved west to Jutland and the "angle" between Jutland and the mainland of Europe, and then from there continued west into England. Presumably they needed
to gather their strength and collect another year's harvest before making the final step.