On the interesting question of the introduction of the barbarians into the frontier provinces, and their incorporation into the legions, he never seems to have quite made up his mind.

In the twelfth chapter he calls it a "great and beneficial plan." Subsequently he calls it a disgraceful and fatal expedient.

He recurs frequently to the subject in isolated passages, but never collects the facts, into a focus, with a view of deducing their real meaning.

Yet the point is second to none in importance.

Its elucidation throws more light on the fall of Rome than any other considerations whatever.