Towns were scarce in it, and country-houses, though not altogether infrequent or insignificant, were unevenly distributed.

At some period not precisely known, perhaps in the first half or the middle of the third century, it was in open rebellion, and the commander of the Sixth Legion (at York), one Artorius Justus, was sent with a part of the British garrison to reduce it to obedience.[1] It may therefore have been, as Mommsen suggests, one of the least Romanized corners of Gaul, and in it the native idiom may have retained unusual vitality.

Yet that native speech was not strong enough to live on permanently.

The Celtic which is spoken to-day in Brittany is not a Gaulish but a British Celtic; it is the result of British influences.
Brittany would have sooner or later become assimilated to the general Romano-Gaulish civilization, had not its Celtic elements won fresh strength from immigrant Britons.

This immigration is usually described as an influx of refugees fleeing from Britain before the English advance.