4. THE ROMAN ARMY—(P. 12)
In his account of the army Gibbon closely followed Vegetius, whose statements must be received with caution. I may call attention here to a few points.
(a) The legion contained ten cohorts; and the cohort, which had its own standard (signum), six centuries. Each century was commanded by a centurion. Under the early Empire, each legion was commanded by a tribunus militum Augusti (under the republic, trib. mil. a populo), who, however, was subject to the authority of a higher officer, the legatus legionis, who was supreme commander of both the legion and the auxiliary troops associated with it. In later times (as we learn from Vegetius) the sphere of the tribune was reduced to the cohort. The number of soldiers in a legion was elastic, and varied at different times. It is generally reckoned at six thousand foot, and one hundred and twenty horsemen (four turmae).
(b) The auxilia included all the standing troops, except the legions, the volunteers (cohortes Italicae civium Romanorum voluntariorum), and of course the praetorian guards. They were divided into cohorts, and were under the command of the legati. Cavalry and infantry were often combined, and constituted a cohors equitata. Each cohort (like the legionary cohort) had its standard, and consisted of six or ten centuries, according to its size, which might be five hundred or a thousand men. To be distinguished from the auxilia were a provincial militia, which appear in certain provinces (such as Rætia, Britain, Dacia). They were not imperial, and were supported by provincial funds (Mommsen, Die röm. Provinzialmilizen, Hermes, xxii. 4).
(c) The use of "artillery" on a large scale was due to Greek influence. It played an important part in the Macedonian army. The fixed number of engines mentioned in the text (ten onagri and fifty-five carroballistae) was perhaps introduced in the time of Vespasian. Vegetius, ii. 25 : Josephus, Bell. Jud. 5, 6, 3.
(d) As for the distribution of the troops, Gibbon arrived at his statement by combining what Tacitus tells of the reign of Tiberius, and what Dion Cassius tells of the reign of Alexander Severus; always a doubtful method of procedure, and in this case demonstrably leading to erroneous results. Under Tiberius in 23 a.d. there were four legions in Upper Germany, four in Lower Germany, three in Spain, two in Egypt, four in Syria, two in Pannonia, two in Dalmatia, two in Moesia, two temporarily removed from Pannonia to Africa. New legions were created by Claudius, Nero, Domitian, &c.; on the other hand, some of the old legions disappeared, or their names were changed. Three new legions (i., ii., and iii. Parthica) were instituted by Septimius Severus. Each legion had a special name. A list of the legions (thirty in number) in the time of Marcus Aurelius will be found in Marquardt, Röm Alterthumer, iii. 2, 356. The history of the Roman legions is a very difficult subject, and the conclusions of Pfitzner (Geschichte der romischen Kaiserlegionen) are extremely doubtful (see Mr. E. G. Hardy in the Journal of Philology, xxiii. 29 sqq.).
(e) The cohortes urbanae had their headquarters in the Forum Suarium (Pig-market) at Rome. They were at first four in number, of one thousand men each, until the time of Claudius, who seems to have increased the number to six; Vespasian perhaps added another. Some of these regiments were sometimes stationed elsewhere; for example, at Lyons, Ostia, Puteoli.
See further article Exercitus in Smith's Dictionary of Antiquities, new edition.
5. THE ROMAN NAVY—(P. 18)
The fleets of Ravenna and Misenum were called the classes praetoriae, a fitting name, as they were the naval guards of the Emperor as long as he resided at Old Rome.
The fleet at (1) Forum Julium was discontinued soon after the time of Augustus. The other lesser naval stations under the Empire were (2) Seleucia, for the classis Syriaca; (3) Alexandria, for the classis Augusta Alexandreae;
