Our querist, however, affirms a diminution of population not only in Italy but throughout the Empire. Here we must first question the assertion. Pestilences, such as that of 166 A.C., doubtless visited most parts of the Empire; but pestilences belong also to the pre-imperial period, and need not here be specially considered. As to Greece, the facts have been already given. The depopulation of that, after Alexander, was primarily a matter of exodus to the richer conquered lands, where a new Hellenistic civilisation arose under purely monarchic rule, and therefore unaccompanied by the all-round, self-developing mental energy which had marked the life of "free" Greece. In Byzantium, of course, the mental stagnation, under Christian autocracy, was no less complete. But there is no evidence whatever that after Constantine the principle of population failed in the Eastern Empire, especially when that was restricted by the amputation of the tributary territories.[431] Did population then fail in Gaul and Spain and Africa? If so, when? As to Gaul, there is evidence that after the conquest population and productivity increased, though the latter had not previously been low--witness the loot taken by Cæsar at Toulouse. Gaul was certainly taxed exorbitantly; but Julian, as we saw, prudently lessened the drain; and Mommsen describes both Gaul and Spain as flourishing in their Romanised period.[432] They continued, in fact, to be, with North Africa, the main sources of the revenue of the Western Empire down to its collapse. Materially, they in some respects went forward, notably in the case of the region of old Carthage. The element wherein they were decadent was precisely that of free manhood, everywhere eviscerated by autocratic and bureaucratic rule. Therefore it was that, like Britain--similarly productive of revenue in the imperial period--they were unable to defend themselves against the final barbarian inroads. Had Honorius carried out his scheme for a measure of Home Rule in Gaul,[433] and followed it up by a similar scheme for Spain, Italy indeed might all the sooner have lost her hold on them as milch kine, but both provinces might conceivably have developed a new life centuries before they historically did.