Diocletian resorted to this arrangement probably as much for reasons of internal as of external policy. For nearly a hundred years before, ever since the death of Commodus, the soldiers had been in the habit of giving or selling the imperial crown, to which any general might aspire. Between thirty and forty emperors had been thus successively made and unmade many of whom only reigned a few months. By fixing upon four colleagues, one in each of the great divisions of the Empire, each having his army, and all mutually checking one another, Diocletian put a stop to military insolence and anarchy. The Empire was no longer put up to sale, the immediate and intolerable evil was effectually cured, though another danger remained, that of disputes and wars between the various sharers of the imperial power; still it was a smaller danger and one which did not manifest itself so long as Diocletian remained at the helm. Writers have been very free of their censure upon this emperor for parcelling, as they call it, the Empire; but this was the only chance there was of preventing its crumbling to pieces. Italy, and Rome in particular, lost by the change: they no longer monopolized the wealth and power of the world, but the other provinces gained. The Empire was much too large for one single man or a single central administration, under the dwindled influence of the Roman name, and amidst the numerous causes of local dissension and discontent, private ambition, social corruption, and foreign hostility, that had accumulated for three centuries, since the time of Augustus. [Illustration: Army on horse. [TN]] The new Caesars justified Diocletian's expectations. Constantius defeated the Franks and the Alemanni, and soon after reconquered Britain. Galerius subjugated the Carpi, and transported the whole tribe into Pannonia. In the year 296, the Persians, under their king Narses, again invaded Mesopotamia and part of Syria. Galerius marched against them, but being too confident was defeated by superior numbers, and obliged to retire. On his meeting Diocletian, the emperor showed his dissatisfaction by letting Galerius walk for a mile, clad in purple as he was, by the side of his car. The following year Galerius again attacked the Persians, and completely defeated them, taking an immense booty. The wives and children of Narses, who were among the prisoners, were treated by Galerius with humanity and respect. Narses sued for peace, which was granted by Diocletian on condition of the Persians giving up all the territory on the right or western bank of the Tigris. This peace was concluded in 297, and lasted forty years.