But one side of his work was lasting and fraught with momentous consequences for the Roman state. It was Marius, the first professional general, who formed the first professional army. We noticed that Greece, even before the end of the fifth century, had already begun to use paid and trained soldiers, partly owing to the unwillingness of her comfortable or busy citizens to engage in annual campaigns, but still more because it was found that the more highly trained and better disciplined mercenaries were far more efficient at their business. So for many centuries Rome had now been the only power in the Mediterranean world to rely upon a citizen militia. That citizen militia had indeed conquered the world; but certainly in dealing with the trained troops of Pyrrhus and Hannibal, the Roman forces had always begun with disaster and slowly been schooled to their trade by defeat. So it was now in the Jugurthan and Cimbric wars: the generals had to train their armies in the face of the enemy, and while that is no doubt the best training ground it is terribly dangerous and expensive. It implies, too, an almost inexhaustible stock of recruits to fall back upon. With the decline of Italian agriculture and the growth of city life the stock of recruits was no longer inexhaustible. Moreover the art of war was becoming more intricate. Rome found it necessary to appoint a genuine soldier for her general against Jugurtha in view of the disastrous failures of aristocratic amateurs. In the same way Marius found it necessary to overhaul the Roman fighting machine, and by the end of his five years of successive consulship he had organised a professional army on much the same system as our own. Rome like England required a highly trained expeditionary force and behind it a large reserve. The principal change instituted by Marius seemed at first a small one and required no legislative sanction. Hitherto the army had consisted only of the propertied classes, the infantry of those who could afford a suit of arms, and the cavalry of the richest citizens who could maintain one of the state horses. The minimum property for a Roman soldier is said to have been £115. The poorest had originally formed a light-armed support, the three middle classes were the line, and the richest the cavalry. But the three classes of the line had by now come to be drawn up not according to property but according to length of service. This was the traditional battle formation of the Roman infantry maniples: [Illustration: (traditional battle formation of the Roman infantry maniples) Triara Principes Hastats]