Now this main instrument, the Roman Army—the instrument, remember, which not only preserved civil functions, but actually created the master of all civic functions, the Government—went through three very clear stages of change in the first four centuries of the Christian era—up to the year A.D. 400 or so. And it is the transformation of the Roman Army during the first four centuries which explains the otherwise inexplicable change in society just afterwards, in the fifth and sixth centuries—that is, from 400 to 600 A.D. The turn from the full civilization of Rome to the beginning of the Dark Ages.

In its first stage, during the early Empire, just as the Catholic Church was founded and was beginning to grow, the Roman Army was still theoretically an army of true Roman citizens. [Footnote: A soldier was still technically a citizen up to the very end. The conception of a soldier as a citizen, the impossibility, for instance, of his being a slave, was in the very bones of Roman thought. Even when the soldiers were almost entirely recruited from barbarians, that is, from slave stock, the soldiers themselves were free citizens always.]

As a matter of fact the Army was already principally professional, and it was being recruited even in this first stage very largely from the territories Rome had conquered.

Thus we have Cæsar raising a Gallic legion almost contemporaneous with his conquest of Gaul. But for a long time after, well into the Christian era, the Army was conceived of in men’s minds as a sort of universal institution rooted in the citizenship which men were still proud to claim throughout the Empire, and which belonged only to a minority of its inhabitants; for the majority were slaves.

In the second phase (which corresponded with the beginning of a decline in letters and in the arts, which carries us through the welter of civil wars in the third century and which introduces the remodeled Empire at their close) the Army was becoming purely professional and at the same time drawn from whatever was least fortunate in Roman society. The recruitment of it was treated much after the fashion of a tax; the great landed proprietors (who, by a parallel development in the decline, were becoming the chief economic feature in the Roman State) were summoned to send a certain number of recruits from their estates.

Slaves would often be glad to go, for, hard as were the conditions of military service, it gave them civic freedom, certain honors, a certain pay, and a future for their children. The poorer freed men would also go at the command of their lord (though only of course a certain proportion—for the conscription was very light compared with modern systems, and was made lighter by reënlistment, long service, absence of reserves, and the use of veterans).

During this second stage, while the Army was becoming less and less civic, and more and more a profession for the destitute and the unfortunate, the unpopularity and the ignorance of military service among the rest of the population, was increasing. The average citizen grew more and more divorced from the Army and knew less and less of its conditions. He came to regard it partly as a necessary police force or defence of his frontiers, partly as a nuisance to him at home. He also came to regard it as something with which he had nothing to do. It lived a life separate from himself. It governed (through the power of the Emperor, its chief); it depended on, and also supported or re-made, the Imperial Court. But it was external, at the close of the Empire, to general society.

Recruiting was meanwhile becoming difficult, and the habit grew up of offering the hungry tribes outside the pale of the Empire the advantage of residence within it on condition that they should serve as Roman soldiers.

The conception of territories within the Empire which were affiliated and allied to it rather than absorbed by it, was a very ancient one. That conception had lost reality so far as the old territories it had once affected were concerned; but it paved the way for the parallel idea of troops affiliated and allied to the Roman Army, part of that army in discipline and organization, yet possessed of considerable freedom within their own divisions.

Here we have not only a constant and increasing use of barbaric troops drafted into the regular corps, but also whole bodies which were more and more frequently accepted “en bloc” and, under their local leaders, as auxiliaries to the Roman forces.