428 THE DECLINE AND FALL CHAP, the emperor less watchful against the well known valour XIII . '__ of the barharians of Europe. From the mouth of the Rhine to that of the Danube, the ancient camps, towns, and citadels, were diligently reestabhshed, and, in the most exposed places, new ones were skilfully constructed; the strictest vigilance was introduced among the garrisons of the frontier, and every expe- dient was practised that could render the long chain of fortifications firm and impenetrable ^. A barrier so re- spectable was seldom violated ; and the barbarians often turned against each other their disappointed rage. Dissensions The Goths, the Vandals, the Gepidae, the Burgun- barians.*^" ^1^"^, the Alemanni, wasted each other's strength by destructive hostilities; and whosoever vanquished, they vanquished the enemies of Rome. The subjects of Diocletian enjoyed the bloody spectacle, and congra- tulated each other, that the mischiefs of civil war were now experienced only by the barbarians K Conduct of Notwithstanding the policy of Diocletian, it was im- rorU'"^^ possible to maintain an equal and undisturbed tran- quilHty during a reign of twenty years, and along a frontier of many hundred miles. Sometimes the bar- barians suspended their domestic animosities, and the relaxed vigilance of the garrisons sometimes gave a passage to their strength or dexterity. Whenever the provinces were invaded, Diocletian conducted himself with that calm dignity which he always affected or pos- sessed ; reserved his presence for such occasions as were worthy of his interposition, never exposed his person or reputation to any unnecessary danger, ensured his success by every means that prudence could sug- gest, and displayed with ostentation the consequences ^ Zosim. I. i. p. 3. That partial historian seems to celebrate the vigilance of Diocletian, with a design of exposing the negligence of Constantine ; we may, however, listen to an orator: "Nam quid ego alarum et cohortium castra percenseam, toto Rheni et Istri et Euphratis limite restituta ?" Pane- gyr. Vet. iv. 18.
- Ruunt omnes in sanguinem suum populi, quibus non contigit esse Ro-
manis, obstinataeque feritatis poenas nunc sponte persolvunt. Panegyr. Vet. iii. 16. Mamertinus illustrates the fact, by the example of almost all the nations of the world.
