Daniel Finkelstein’s post on the ten worst mistakes in British history is one of the most fascinating things I’ve seen on the Web in some time. But he (and, unless I’ve overlooked something, all but one of his respondents) have overlooked a big one: Vortigern’s bright idea of bringing the Saxons over to defend post-Roman Britain. I go into this in my introduction to Gildas’ On the Ruin of Britain:
The vagaries of fourth century Rome, with its combination of increasing centralisation and taxation and the progressive unravelling of Roman power with the barbarian invasions, fell hard on Britain, with characters like Paul the Chain making life for the local notables difficult. Around the sack of Rome in 410, Britain’s power holders, believing that the obligations of Roman rule outweighed the unavailable benefits, simply threw off Roman rule and went to a form of self-government. It is not clear how they organised themselves in the wake of this but there is no evidence of a strong central authority figure.
This independence did not end the problem of the barbarian invasions. At this point the British chief Vortigern got the bright idea of inviting the Saxons into the eastern extremeties of England–the usual jumping-off point for barbarian invasions from the Continent, as Hitler planned in 1940–to defend the island. Vortigern’s colleagues went along with the plan, the Saxons were invited, and when they came they became part of the problem rather than part of the solution, eventually destroying Roman Britain and driving its survivors into Wales, Cornwall and Brittany.