[Kynaston+1]

The last 'Roman' troops were withdrawn by Constantine 111 in his bid for imperial power, after which the British authorities relied on mercenaries, for which reason they kicked out the imperial oficials in 410. As is shown by reports of the visits of Germanus a good deal later, the provinces of Britain remained prosperous, and there is plenty of evidence of trade with the Mediterranean for a very long time afterwards. If the Rescript of Honorius was really a reply to a pro-imperial British party or (as has been argued) to an Italian city doesn't seem very relevant: Britain was an independent Roman state (its citizens 'Roman' in a new context, its official language Latin) and was not about to become anything else by choice. Here's Zosimus on the barbarian attack of 409, by the way, to indicate that 'the Romans' (i.e. the imperial officials) didn't 'voluntarily withdraw':

'(Constantine, in 409) allowed the barbarians over the Rhine to make unrestricted incursions. They reduced the inhabitants of Britain and some of the Gallic people to such straits that they revolted from the Roman empire, no longer submitted to Roman law and reverted to their native customs. The Britons, therefore, armed themselves and ran many risks to ensure their own safety and free their cities from the attacking barbarians. The whole of Armorica and other Gallic provinces, in imitation of the Britons, freed themselves in the same way, by expelling the Roman magistrates and establishing the government they wanted.'

The whole period is being re-examined in the light of the archaeological evidence. Obviously it's a subject where a great deal of Athurian and other hogwash whooshes about in the darkness, but Christopher Snyder's 'An Age of Tyrants - Britain and the Britons A.D. 400 - 600' (Sutton, 1998) seems pretty sound.

[BurrsWogdon]

Romans lost interest in conquering Caledonia

The Danes didn't seem to take much "interest" either. That's like a euphemism for "it's full of Scots!".