The chief sources of information are the sculptured reliefs on the sepulchral monuments of the soldiers themselves and on the columns of Trajan and Marcus. Excavations have also yielded specimens, very badly damaged in most cases, of the weapons and armour in use at different periods. The literary authorities contain little that is valuable, with the exception of Arrian’s description of cavalry uniform and equipment in his own day.374

On sepulchral monuments of cavalry soldiers dating from the first century375 the deceased is usually represented on horseback in the act of spearing a fallen enemy. It may be assumed, therefore, that the armour and weapons represented are those actually used in warfare, in other words that these men are in ‘service uniform’. At this period the cavalry uniform consisted of a tunic, breeches reaching a little below the knee, both probably of leather, and the caligae or military boots. Over the tunic was worn a leather breastplate with extra shoulder-pieces to guard against a down cut. Metal breastplates however, although rare, are not unknown. Scale armour is worn by a trooper of the Ala Longiniana represented on an early Rhenish relief,376 and also appears on two African reliefs of early date representing equites of the Cohors VI Dalmatarum.377 The shield is usually an oblong with the longer sides slightly curved, but occasionally an angle in these longer sides transforms it into an elongated hexagon. This shield was borrowed from the Celtic or Teutonic tribes, as is shown by its frequent appearance on the reliefs in the hands of the fallen barbarian. To judge from these reliefs it measured about one foot by three, and was probably of wood covered with leather.

The helmet, which was of metal, had a projection behind to cover the neck in the manner of the English cavalry helmet of the seventeenth century. It was also furnished with an extra band of metal or a peak in front to protect the forehead and large cheek-pieces which clasped over the chin. On the monument of a trooper of the Ala Noricorum,378 a very good example of this class, the cheek-pieces are highly ornamented and the top of the helmet is ridged to represent hair. The crest does not appear, probably because it was not worn on active service.379 It is equally absent from the battle-scenes of the Trajan column, although the ring to which it was fastened is shown. Some fine plumes are, however, represented on the helmet of a standard-bearer of the Ala Petriana on a British relief, which probably dates from the end of the first century.380

The long broadsword or spatha, the characteristic weapon of the auxiliaries,381 which was probably, like the shield, of Celtic origin,382 was worn on the right side suspended from the left shoulder by a sword belt (balteus). The hilt ended in a large knob-shaped pommel, and the sheath was often highly ornamented.

The lance with which the soldier strikes his prostrate adversary appears to have had a shaft about six feet long and a broad head. Two more spears often appear on these sepulchral reliefs in the hands of an attendant in the background. These are probably the throwing spears which were carried, according to Josephus,383 in a quiver on the back, and could not therefore, owing to the position of the rider, be represented in their proper place. Concerning the horses one can say little except that they can hardly have been so small as they are represented. The saddle has a high pommel and cantle and is sometimes covered with a fringed cloth, and the junctures of the harness are ornamented with metal plates (phalerae). Like all ancient cavalry the auxiliaries rode without stirrups.

From these reliefs, therefore, we can construct a fairly complete picture of the auxiliary cavalryman of the pre-Flavian period. His equipment as he appears on the column of Trajan is essentially the same, except that he now wears a shirt of chain-mail over his tunic instead of the leather breastplate, and that his shield has changed from an oblong to a narrow oval.384 It is hardly necessary now to defend the accuracy of the column in matters of detail, but it may be mentioned that there is further testimony for each of these changes.385

Chain-mail appears on the Adam Klissi reliefs and is mentioned by Arrian,386 and the oval shield is shown on a Rhenish relief dating from the end of the first century.387 The varied scenes represented on the column enable one also to notice further points, such as the manner in which the shield is slung at the side of the saddle when troops are on the march,388 and the use of the military cloak (sagum) which hung down the back and could not therefore appear on the sepulchral reliefs.389

In addition to this service uniform there was, as Arrian’s description shows, a sort of parade uniform in which the mail shirts were replaced by brightly coloured tunics, and lighter shields and spears were carried than those used in war.390 It was with this uniform and on ceremonial occasions that some of the soldiers wore those curious helmets with a mask decorating the face of which several specimens have been found.391 The fine scale armour which has been found at Newstead and elsewhere probably also formed part of this parade uniform. It is, indeed, always worn by the Praetorians on the Marcus column, but the auxilia still appear in chain-mail as on the column of Trajan.392 Specially elaborate suits of this armour were, however, worn by the regiments of catafractarii who appear in the army list in the second century.393 The last change which we can trace was the alteration of the shape of the shield from oval to round, which probably took place in the third century. An eques of the Cohors I Thracum is represented on a Danubian sepulchral monument with a shield of this form,394 and the contemporary reliefs on the arch of Constantine show that it was practically universal a century later.

The equipment described above was worn by the majority of the auxiliary cavalry, but it was by no means universal. The horse archers, if one may judge by a soldier of the Ala I Augusta Ituraeorum represented on a Danubian relief, carried no shield, and possibly no body armour, and wore a leather cap in place of a helmet.395 Arrian also mentions that some regiments carried a specially heavy spear (κοντός), and devoted themselves to shock tactics.396 The numeri, too, did not adopt the Roman uniform, but kept to their own dress and weapons. The Moors of Lusius Quietus are represented on the column wearing nothing but a short tunic; their weapons consist of a spear and a small round buckler (cetra), and they ride their horses without saddle or bridle, guiding them simply by a halter round the neck.397 The regiments of Sarmatae enrolled by Marcus also presumably wore their national costume, which is perhaps represented in a fragmentary relief in the Chester Museum.398

The equipment of the auxiliary infantry in the first century is more difficult to determine. Not only did the soldiers of the cohorts erect fewer sculptured monuments than the cavalry troopers, but on these reliefs the deceased is not represented in the act of fighting, so that we cannot be certain that he appears in full service uniform. One of the best of the early monuments is the tombstone of a soldier of Cohors IV Dalmatarum from the Rhine.399 The deceased is dressed in a short tunic, which is looped up at the sides so as to hang down in front in a series of folds. The sagum covers his shoulders and hangs down his back. A long spatha and a short dagger are suspended from two waist-belts (cingula) at his right and left side respectively. He has no body armour except a kind of sporran composed of strips of metal which extends from the middle of his belt to the bottom of his tunic. His legs are bare, and he wears no helmet. In his right hand he holds two long spears and in his left an oblong rectangular shield, which is not curved like the legionary scutum but flat as a board. On two other reliefs a soldier of the Cohors I Pannoniorum400 and an archer of the Cohors I Sagittariorum401 are represented in a similar costume, except that the Pannonian wears the paenula instead of the sagum, and that the archer carries a bow and arrows in place of the shield and spears.

If these soldiers are fully equipped they have surprisingly little defensive armour, but on other monuments, notably those of a private of the Cohors II Raetorum,402 and a standard-bearer of the Cohors V Asturum,403 a leather breastplate appears similar to that worn by the cavalry at this period. On the Trajan column too, the auxiliary infantry are furnished like the cavalry with metal helmet and chain-mail shirt and wear the short tunic and bracae.404 Professor von Domaszewski would like to see in all this a development of the auxiliaries from light into heavy infantry,405 and it is true that in his account of the German campaigns in the reign of Tiberius, Tacitus emphasizes their character as light-armed troops.406 But even on the Trajan column they are still lighter armed than the legionaries, and the evidence of the monuments is far from decisive. The tombstones of legionaries of the same period represent them wearing a leather breastplate, although there is no reason to suppose that the so-called lorica segmentata was not yet in use. On the whole it seems safer to fall back on the hypothesis that on some of these monuments the deceased is represented in a parade uniform with which, as in the case of that described by Arrian, the breastplate was not worn. The tunic with its elaborate folds may also form part of this costume, since we know from the cavalry reliefs that the short leather tunics and bracae were already in use.

The Trajanic reliefs show several varieties of uniforms in addition to the ordinary type described above. The flying column which the emperor leads down the Danube includes men who wear, instead of the ordinary helmet, an animal’s skin arranged over the head and shoulders in the manner usually confined to standard-bearers, and others whose helmets are of a curious Teutonic pattern.407 These may belong to regular cohorts which had been allowed to retain something of their national costume, but a barbarian who appears in this scene and elsewhere clad only in long loose breeches and a sagum, and whose chief weapon is a knotted club, must represent a numerus. Others of these irregular regiments are probably represented by the archers clad in long tunics and pointed caps or wearing helmet and shirt of scale armour who appear in one or two scenes.408 They are certainly to be distinguished from the archers of the cohortes sagittariorum, who appear in a uniform which only differs from that of the ordinary auxiliary infantry in the absence of the shield.409 The most exceptional uniform is that of the slingers, who are dressed simply in tunics with no armour but a shield.410 Cichorius411 wishes to recognize in them men from the Balearic Islands, but although the Baleares were employed by the Republic we have no inscriptions of a Cohors Balearum under the Empire. Moreover, if there existed cohorts of slingers with this distinctive uniform we should expect to find cohortes funditorum or libritorum on the analogy of the cohortes sagittariorum. It appears, on the contrary, from a passage in Hadrian’s speech to the African army that slinging formed part of the general training of all the auxilia.412 Like the cavalry, the auxiliary infantry are represented on the Marcus column in a uniform essentially the same as that worn eighty years previously, and no further developments can be traced. The most striking fact which emerges from this inquiry is the general uniformity of the equipment of nine-tenths of the auxiliary regiments in the second century. We learn from casual references in Tacitus that this uniformity had always been the ideal of the Roman War Office,413 and from the military point of view there was doubtless much to recommend it.

It has, however, more significance if we regard it as one phase in that extension of a uniform material culture through at any rate the western half of the Empire which marks the first and second centuries.