[image ALT: Much of my site will be useless to you if you've got the images turned off!]
Bill Thayer

[image ALT: Cliccare qui per una pagina di aiuto in Italiano.]

[Link to a series of help pages]
[Link to the next level up]
[Link to my homepage]

 p244  Castra

Article by William Ramsay, M.A., Professor of Humanity in the University of Glasgow
on pp244‑256 of

William Smith, D.C.L., LL.D.:
A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875.


It is well known that Roman armies never halted for a single night without forming a regular entrenchment, termed castra, capable of receiving within its limits the whole body of fighting men, their beasts of burden, and the baggage. So essential was this operation considered, that even when preparing for an immediate engagement, or when actually assailed by a hostile force, it was never omitted, but a portion of the soldiers were employed in constructing the necessary works, while the remainder were standing to their arms or resisting the enemy; and so completely was it recognised as a part of the ordinary duties of each march, that pervenire ad locum tertiis . . . quartis . . . septuagesimis castris are the established phrases for expressing the number of days occupied in passing from one point to another. Whenever circumstances rendered it expedient for a force to occupy the same ground for any length of time, then the encampment was distinguished as castra stativa (Liv. XXVII.12; Caes. B. G. VIII.15, Caes. B. C. 1.42; Hirt. B. Af. 51, B. Al. 74).

When the protracted and distant wars in which the republic became engaged, as its sway was gradually extended first over the whole of Italy, and subsequently over Greece, Asia, and Africa, rendered it impossible for the legions to return home in winter, they usually retired during the months when active military operations were suspended, into some city where they could be protected from the inclemency of the season, and where the comforts of the men could be readily secured; or they were dispersed up and down in detachments among friendly villages (in hiberna concedere; exercitum in hiberna dimittere; exercitum per civitates in hiberna dividere). It is true that extraordinary emergencies, such as a protracted blockade, or the necessity of maintaining a constant watch upon the movements of a neighbouring and vigorous foe, might compel a commander to keep the field for a whole year or even longer, but to order an army, except in case of necessity, to winter under canvass (hiemare sub pellibus; hiemem sub tentoriis exigere) was long regarded as a severe punishment, inflicted only in consequence of grievous misconduct (Frontin. Strat. IV.1 §24). As the boundaries of the empire were gradually pushed forward into wild and barbarian lands, where there were no large towns and no tribes on whose faith reliance could be placed, such arrangements became impracticable, and armies, whether of invasion or occasion, were forced to remain constantly in camps. They usually, however, occupied different ground in summer and in winter, whence arose the distinction between castra aestiva and castra hiberna, both alike being stativa. Such posts were frequently, if situated advantageously, garrisoned permanently; and the peaceful natives who sought to enrich themselves by trading with their conquerors, settled for security in the immediate vicinity (Caes. B. G. VI.37). Thus in the distant provinces, these forts formed a centre round which a numerous population gradually clustered; and many important towns, still existing in our own country, indicate their origin by the termination chester.

But whether a camp was temporary or permanent, whether tenanted in summer or in winter, the main features of the work were always the same for the same epoch. In hiberna, huts of turf or stone would be substituted for the open tents of the aestiva (hence aedificare hiberna), and in stativa held for long periods the defences would present a more substantial and finished aspect, but the general outline and disposition of the parts were invariable: a camp was laid down, arranged and fortified according to a fixed and well-known plan, modified only by the numbers for whom it was required to provide accommodation, but altogether independent of the nature of the ground or of the fancy of the general, so that each battalion, each company, and each individual, had a place assigned to which they could at once repair without order, question, delay, or confusion.

At what period the practice of throwing up elaborate field-works for the protection of an army engaged in active service was first commenced by the Romans, it is impossible to determine; but we may safely conclude that, like all other parts of their military tactics, it was matured by a slow and gradual process. Livy and Dionysus, indeed, would lead us to suppose that regular camps existed from the most remote epoch to which their annals extend; but the language of these historians is in general so loose upon all matters of antiquarian research, and they are so much in the habit of transferring to the earliest ages the usages of their own contemporaries, that no safe inference regarding points of this nature can be drawn from their words. Frontinus, on the other hand, declares that the idea of a fortified enclosure, calculated to contain a whole army, was first suggested to the Romans by the camp of Pyrrhus, which they captured near Beneventum; but the statements of this author have never been deemed to possess much weight, and in this particular instance many considerations preclude us from admitting his testimony as credible. It is evident, however, from the facts detailed in the article Exercitus that a camp, such as the earliest of those of which we possess any detailed account, could not have assumed that shape until the tactics of the phalanx were superseded by the manipular divisions; and it may be held as certain that each of the great wars in which the Commonwealth was successively engaged for more than a century — with the Samnites, with Pyrrhus, with the Cisalpine Gauls, and with the Carthaginians, must have led to a series of improvements. The system was probably brought to perfection in the campaigns against Hannibal, and underwent no material alteration until the organic changes in the constitution of the army, which took place not long before the downfall of the constitution, during the civil broils, and under the earlier emperors, rendered a corresponding change in the internal economy of the camp unavoidable. Hence, although it would be at once vain and unprofitable to attempt an investigation of the various changes through which a Roman camp passed before it assumed what may be called its normal shape, it is evidently absolutely necessary for all who desire to obtain even a slight knowledge of the Roman art of war, to make themselves acquainted with this important feature in their system during the best days of the republic and the empire. And fortunately the records of antiquity enable us to supply such information with considerable minuteness. Polybius, the friend and companion of the younger Scipio, has transmitted to us a description of a Roman camp, such as he must have often seen with his own eyes, and a certain  p245 Hyginus, a gromaticus or land surveyor, who flourished under Trajan and Hadrian, has left us a technical memoir on the art of castrametation as practised in his own day. To these some might feel inclined to add the remarks of Vegetius, who lived during the reign of Valentinian, but for reasons which are stated elsewhere it will be more safe to neglect him altogether.

We shall proceed to describe these two camps in succession, it being understood that the leading statements with regard to the first are taken directly from Polybius, and those with regard to the second, from Hyginus, unless when the contrary is distinctly indicated. But while we endeavour to explain clearly all the parts of the camps themselves, we must refer to the article Exercitus for everything that concerns the different kinds of troops, their divisions, their discipline, and their officers.

A. Camp of Polybius.

The camp described by Polybius is such as would be formed at the close of an ordinary day's  p246 march by a regular consular army consisting of two Roman legions with the full contingent of Socii. Each legion is calculated at 4200 infantry and 300 cavalry, the Socii furnished an equal number of infantry and twice as many cavalry, so that the whole force would amount to 16,800 foot and 1800 horse.

Choice of the Ground.— Although, as stated above, the general outline, the defences, and the internal economy of a camp were altogether independent of the nature of the ground, yet great importance was attached to the choice of a fitting situation which should admit of being readily laid out in the required form, which should afford no facilities for attack or annoyance, which should be convenient for procuring wood, water, and forage, and which the army might enter and quit without danger of surprise. Skill in the selection of such a spot (capere locum castris) was ever considered as high quality in a general, and we find it recorded among the praises of the most renowned commanders that they were wont in person to perform this duty (e.g. Liv. IX.17, XXXV.14, 28; Tac. Hist. II.5, Agric. 20; comp. Quintil. I.O. XII.3 §5). Under ordinary circumstances, however, the task was devolved upon one of the military tribunes, and a certain number of companions appointed from time to time for the purpose. These having gone forward in advance of the army until they reached the place near which its intended to halt, and having taken a general survey of the ground, selected a spot from whence a good view of the whole proposed area might be obtained, that spot being considerably within the limits of the contemplated enclosure.

Construction.— The spot answering these conditions and which we shall call A (fig. 1) was marked by a small white flag. The next object was to ascertain in what direction water and fodder might be most easily and securely provided — this direction we indicate by the arrow in the subjoined figure. Upon the position of A and the direction of the arrow depended the disposition of all the other parts of the work; for these two preliminary points being decided, the business of measuring out the ground (metari castra) commenced, and was executed, as we learn from various sources, with graduated rods (decempedae) by persons denominated metatores. The different steps of the process may be most briefly and distinctly set down in the ordinary language of a geometrical construction.

Through A draw a straight line A0A1, parallel to the direction of the arrow, a straight line B0B1, at right angles to A0A1. These two straight lines A0A1 and B0B1, served as the bases by which the position of all the different divisions of the camp were determined.

Along AA0 set off AA2 = 100 feet; A2A4 = 50 feet; A4A5; A5A6; A6A7; A7A8; A8A9; A9A10 each = 100 feet; A10A11 = 50 feet; A11A12; A12A13; A13A14; A14A15; A15A16 each = 100 feet; A16A17 = 200 feet.

Along AA1 set off AA3; A3A18, each = 100 feet; A18A19 = 167 feet; A19A20 = 200 feet.

Through A2; A3; A4; A5; A17; A18; A19; A20 draw C0C1; D0D1; E0E1; F0F1; G0G1; H0H1; K0K1; L0L1 straight lines parallel to B0B1, and in like manner draw through A6; A7; . . . A16 straight lines parallel to B0B1, as marked in the figure.

On B0B1 make AB2; AB3 each = 100 feet.

Through B2 and B3 draw straight lines parallel to A0A1 cutting C0C1 in C2 and C3, and cutting D0D1 in D2 and D3; in this manner a square area C2C3D3D2 is determined, each side of which = 200 feet.

Along A5F0 set off A5P = 25 feet; PQ = 100 feet; QR = 50 feet; RS = 50 feet; ST = 100 feet; TV = 100 feet; VW = 50 feet; WX = 133½ feet; XY = 200 feet; YZ = 200 feet.

Along A5F1 set off A5P′; P′Q′; Q′R′ . . . Y′Z′, equal respectively to A5P; PQ; QR; . . . YZ.

Through ZZ′ draw straight lines parallel to A0A1, cutting G0G1 in z and z′, and cutting L0L1 in O and O′. The square area OO′z′z thus determined was the camp.

Again, through P; Q; R . . . Y, and through P′; Q′; R′ . . . Y′ draw straight lines parallel to A0A1, cutting the parallels to B0B1 in the points marked in the figure.

Finally, on H0H1 lay off A18H3 and A18H4 each = 25 feet, and through H3; H4; draw straight lines parallel to A0A1, cutting K0K1 in K3 and K4.

This construction being completed we now proceed to explain the arrangement of the different parts referring to figure 2, in which the lines no longer necessary are obliterated, the spaces occupied by the troops or officers enclosed by dark lines, and the streets (viae) distinctly laid down. In practice the most important points were marked by white poles, some of which bore flags of various colours, so that the different battalions could at once discover the place assigned to them.

The white flag A, which served as the starting point of the whole construction, marked the position of the consul's tent, or praetorium, so called because praetor was the ancient term for any one invested with supreme command. The square area C2D3 was left open extending, as we have seen, a hundred feet each way from the praetorium. That portion of the camp which lay in the direction of the arrow (πρὸς τὴν ἐκτὸς ἐπιφάνειαν) from the line E0E1 (fig. 1) was termed the front or fore-part of the camp (τοῦ παντὸς σχήματος κατὰ πρόσωπον).

The number of legions being two and the number of tribunes in each being six, their tents were arranged six and six at equal distances along the line E0E1 (fig. 1) exactly opposite to and looking towards the legions to which they belonged. Hence, as will be seen from what follows, they did not extend beyond the points E3and E4, but whether they were distributed at equal distances along the whole of the line E3E4, or whether the space in front of the praetorium was left vacant, as in our figure, as seems most probable, may admit of doubt. The space of fifty feet included between the parallels C0C1 and E0E1 (fig. 1), immediately behind the tents of the tribunes, was appropriated to their horses, beasts of burden and baggage.

The ten area marked 1 were set apart for the cavalry of one legion, and the corresponding ten areas marked 1′ for the cavalry of the other legion. These all faced towards the street PP′, and each area, containing a space of 10,000 square feet, was allotted to one turma or troop of 30 dragoons, with their horses and baggage.

 p247  Back to back with the cavalry, and looking out upon the streets RS, R′S′, the Triarii of the two legions were quartered in the areas 2 and 2′. Each area contained 5000 square feet, and was allotted to a maniple of 60 men; hence, according to the calculation here followed, a dragoon and his horse were allowed as much space as 4 foot soldiers.

In the areas marked 3 and 3′ facing the Triarii were quartered the principes of the two legions; each of these areas contained 10,000 square feet, and was allotted to a maniple of two centuries, that is, 120 men.

In the areas marked 4 and 4′, back to back with the principes, and looking out upon the streets VW, V′W′, were quartered the Hastati of the two legions, the number of men being the same as in the Principes, and an equal space being assigned to them.

Facing the legionary Hastati, in the areas marked 5 and 5′, were the cavalry of the allies. The total number was 600 to each legion, but of those ⅓ or 200 were separated under the name of extraordinarii, and quartered in a different part of the camp. Consequently, each of the spaces 5 and 5′ was calculated to accommodate 40 dragoons with their horses; and allowing them the same space as the legionary cavalry, each of these areas must have contained somewhat more than 13,333 square feet.

Back to back with the cavalry of the allies, and looking towards the rampart which enclosed the camp, the infantry of the allies were quartered in the areas marked 6 and 6′. The total number was 3000 for each legion, but of these ⅕ or 600 were separated as extraordinarii and quartered in a different part of the camp. Hence there would remain 2400, or 240 for each of the spaces 6 and 6′, and these accordingly contained 20,000 square feet.

The open space immediately next to the tents and baggage of the tribunes, extending to the right  p248 and left of the space allotted to the general, was assigned on one side to a forum, and on the other, to the quaestor and his department (τῷ δε ταμίᾳ, ταὶς ἅμα τούτῷ χορηγίαις). These are marked 7 and 8, but we are not told on which side they respectively stood.

Still further to the right and left of the praetorium in 9, 10, and 9′, 10′, looking respectively towards the forum and the quaestorium, were a body of cavalry, selected from the extraordinarii equites (οἱ τῶν ἐπιλέκτων ἱππέων ἀπόλεκτοι), and a body of cavalry serving as volunteers out of compliment to the general (καί τινες τῶν ἐθελοντηδὸν στρατευομένων τῇ τῶν ὑπατων χάριτι), analogous, probably, to the Evocati of later times. Back to back with these, looking towards the rampart, in 11, 12 and 11′c 12′, were quartered the foot-soldiers belonging to the same classes as the cavalry just named. On the march, these troops were always near the person of the consul and of the quaestor, and served as a sort of body-guard to them. Their number is nowhere specified, and hence the exact piece required for their accommodation cannot be determined.

In 13 and 13′, looking towards the quaestorium, praetorium, and forum, were quartered the remainder of the extraordinarii equites. Back to back with these, facing the ramparts in 14 and 14′, were the remainder of the extraordinarii pedites. The spaces marked 15, 15′ on the flanks of 13, 14, 13′, 14′, were assigned to foreign troops or to allies not included in the regular contingent, who might chance to be present (τοῖς ἀλλοφύλοις καὶ τοὶς ἐκ τοῦ καιροῦ προσγιγνομένοις συμμάχοις).

The form of the camp was an exact square (τετράγωνον ἰσόπλευρον), the length of each side being 2017 Roman feet.

The clear space between the ramparts and the tents (intervallum) was 200 feet, and this was of the greatest service in facilitating the marching in and out of the soldiers without crowding or confusion. Here, also, cattle and other booty were kept and guarded; and the breadth was sufficient to prevent any ordinary missile or fire-brand hurled into the camp from doing serious injury.

The principal street, stretching right across in front of the tents of the tribunes, was 100 feet wide and was named Principia. It will be observed that the lengthened lines of the ten turmae and manipuli in each division is intersected at the termination of the first five by a road fifty feet wide, called the Via Quintana. The position of the remaining five viae in the fore-part of the camp, all of which intersect the Via Quintana at right angles, will be understood at once by inspecting the plan, the width of each being 50 feet.

When two consular armies encamped together within the same rampart, two ordinary camps were, it may be said, applied to each other at the ends nearest to their respective praetoria. The two praetoria faced in opposite directions, and the legions of the two consuls stretched their lines in front of each praetorium, so that the figure of the camp was now no longer a square, but a rectangle, whose length was twice that of an ordinary camp, the breadth being the same.

Although the words of Polybius are, as a whole, so full and clear that we can have little difficulty in forming a distinct conception of the camp which he describes and in delineating the different parts, it must not be concealed that he has altogether passed over many important points on which we should desire information, and that occasionally his language is not entirely free from ambiguity.

Under the head of omissions, we must note —
  1. The absence of all information with regard to the manner in which the Velites were disposed of. These, at the time when Polybius wrote, amounted to 1200, or, at the lowest computation, to 1000 for each legion; and taking the same number for the contingent of the Socii, we shall thus have a body of at least 4000 men unprovided for. It is true that he subsequently states, in a passage which we quote below, that the velites kept guard by night and by day along the whole extent of the rampart, and that they were stationed in bodies of ten to watch the gates. Hence some have supposed that the light-armed troops always bivouacked outside the camp; others, that they occupied the interval um; others, that, just as in the line of battle, they did not form a distinct corps, but were divided among the hastati, principes, and triarii, according to a given ratio, so in like manner they were, in the camp, quartered along with those divisions to which they were attached in the field. The velites ceased to form a portion of the legion about the time of Marius, and consequently the later Roman writers throw no light upon the question. It is remarkable, also, that while Polybius passes them over completely in the internal arrangements of his camp, so also he takes no notice whatsoever of them when describing the agmen or the order of march in which an army usually advanced.
  2. No mention is made of the legati. Lipsius, in his plan of a Roman camp after Polybius, assigns to them a compartment next to the praetorium on the side opposite to that where the quaestorium stood; but this is merely a conjecture.
  3. The praefecti sociorum likewise are passed over. Since they corresponded among the troops of the allies to the tribuni in the legions, it seems highly probable that their tents were ranged along a prolongation of the line on which the latter stood, and thus they also would be placed immediately opposite to and looking towards the soldiers under their immediate command.
  4. The number of tents allowed to each maniple or century is nowhere stated, and consequently the number of men in each tent is unknown, nor are we very distinctly told how the centurions and other officers of the infantry and cavalry inferior to the tribunes were provided for; it is merely said that the ταξίαρχοι in each maniple took the first tents on each side, that is, probably, at each end of the row which held one maniple.
  5. With regard to the fortifications of the camp it is stated that the digging of the ditch (ταφρεία) and the formation of the rampart (χαρακοποιία) upon two sides of the camp was assigned to the socii, each division taking that side along which it was quartered; while the two remaining sides were in like manner completed by the legionaries, one by each legion. The work upon each side was portioned out among the maniples, the centurions acted as inspectors of the tasks performed by their respective companies, and the general superintendence was undertaken by two of the tribunes. The nature and the dimensions of the defences are not, however, specified. These consisted of a ditch (fossa), the earth from which was thrown inwards, and formed, along with turf and  p249 stones, into a mound (agger), on the summit of which a strong palisade of wooden stakes (sudes, valli) was fixed forming the rampart (Vallum s. Vallusχάραξ). We can scarcely doubt that the depth of the ditch, together with the height and breadth of the agger, were, under ordinary circumstances, fixed; but the measurements incidentally mentioned in isolated passages do not perfectly accord with each other. Among the works at Dyrrhachium (Caes. B. C. III.63) we read of a ditch 15 feet deep, and a vallum 10 feet high and 10 feet broad; in the war against the Bellovaci and other Gaulish tribes we find Caesar (B. G. VII.9) fortifying his camp with a double ditch, 15 feet deep, with perpendicular sides (directis lateribus), and a vallum 12 feet high, on the top of which was a breastwork (loricula) and numerous towers three stories high connected with each other by bridges, the sides of these bridges next to the enemy being protected by a breastwork of fascines (viminea loricula). Both of these, however, as well as several others which we might quote, must be regarded as special cases. The practice of a later period is, as we shall see below, more clearly defined by Hyginus and others.

6. Neither the number nor the names of the openings in the vallum are given. We have abundant evidence to prove that there were four:— (1) Porta Principalis dextra and (2) Porta Principalis sinistra at the two extremities of the wide street called Principia; (3) Porta praetoria s. Extraordinaria, so called from being situated on that side of the camp nearest to the praetorium and in the immediate vicinity of the quarters of the extraordinarii; (4) Porta Decumana, so called from being situated on that end where the tenth turmae and tenth maniples in each division were quartered. This gate was also called Porta Quaestoria, in consequence, it would seem, of the Quaestorium and the Forum having been at one time placed in its vicinity, and here unquestionably stood the Quaestorium in the camp of Hyginus, as we shall see below. Festus likewise has the gloss "Quintana appellatur porta in castris post praetorium, ubi rerum utensilium forum sit," and from Quintana in the sense of Forum comes the modern Canteen. The perplexity caused by these statements had induced some critics to reverse the positions of the Porta Praetoria and the Porta Decumana as marked in our plan; but this alteration will give rise to difficulties still more serious, as may be seen from consulting Polybius and the authorities referred to at the end of this paragraph; for we find it expressly stated that the Porta Decumana was on that side of the camp most removed from the enemy (abs tergo castrorum; aversa castrorum; decumana maxime petebatur aversa hosti et fugientibus tutior), leading out, as will be seen from the construction, in the direction from which wood, water, and other necessary supplies would be most easily and securely provided. (Liv. XL.27, III.53, X.32, XXXIV.47; Tac. Ann. I.66, IV.30; Festus, s.vv. Praetoria porta, Principalis, Quintana; (Sueton. Ner. 26.)

We can scarcely doubt that the Portae must have been always defended by barriers of some kind; but when special precautions were required they were closed by regular gates defended by towers (portis fores altioresque turres imposuit, Caes. B. G. VIII.9).
  7. In which direction did the Praetorium face? towards the Porta Praetoria or towards the legions and the Porta Decumana? On the reply to this question, which can be answered from conjecture only, depends the solution of the problem as to which was the Porta Principalis dextra and the P. P. sinistra. In like manner we cannot ascertain on which side of the Praetorium the Quaestorium was placed. But these are matters of small moment.

The above are the most important omissions in the description of Polybius. Our limits will not permit us to do more than simply to indicate one important point where a certain degree of ambiguity in his phraseology has given rise to doubt, discussion, and an irreconcilable difference of opinion. After detailing the arrangements adopted when two consular armies encamp together, he adds these remarkable words — ὅταν δὲ χωρὶς τ’ ἄλλα μεν ὡσαύτως, τὴνδ’ ἀγορὰν, καὶ τὸ ταμιεῖον, καὶ τὸ στρατήγιον, μέσον τιθέασι τῶν δυοῖν στρατοπέδων. Taking this sentence by itself, if the text be pure, and if the word στρατοπέδων be rendered, as apparently it must be rendered, legions, then we should be led to the conclusion that in a single camp, the Praetorium, the Quaestorium and the Forum were all situated somewhere about the middle of the Via Quintana; and this conclusion Schelius, one of the most acute and learned writers on the military affairs of the Romans, has actually adopted. This, however, is so completely at variance with the whole previous narrative of the historian who occupies himself from the commencement with a single consular camp, and lays down the site of the praetorium, as we have done above, in a manner so clear as to admit of no cavil, the whole construction, in fact, depending upon the spot thus assigned to the praetorium, that we are driven to make choice of one of these alternatives, either that there is a corruption lurking in the text, or that Polybius is here alluding to some peculiar expedient which was resorted to when two consular armies encamped beside each other, but were not actually included within the lines of a single camp. For a full and fair examination of this and other difficulties which suggest themselves upon a close examination of Polybius and an impartial review of the chief arguments adduced by contending critics, the student may consult a tract entitled "Polybii Castrorum Romanorum formae interpretatio, scripsit G. F. Rettig," 4to. Hannov. 1828.

We now proceed to notice various particulars connected with the internal discipline of the camp.

The Camp Oath.— When an army encamped for the first time, the tribunes administered an oath to each individual quartered or employed within its limits, including slaves as well as freemen, to the effect that he would steal nothing out of the camp, but if he chanced to find any property that he would bring it to the tribunes. We must suppose that the solemn promise being once made, was considered as binding during the whole campaign, for it would have been impossible to have repeated a ceremony so tedious at the close of each march.

Distribution of Duty among the Officers Oath.— In each legion the tribunes divided themselves into three sections of two each, and each section in turn undertook for two months the superintendence of all matters connected with the camp. It is not improbable that one tribune in each section assumed the chief command upon alternate days, or perhaps during alternate months, and hence Polybius generally  p250 speaks of one tribune only as acting, or of two when reference is made to both legions.

Officers parade.— Every morning at day-break the centurions and the equites presented themselves before the tents of the tribunes, and the tribunes in like manner, attended perhaps by the centurions and equites, presented themselves at the praetorium. The orders for the day were then issued by the consul to the tribunes, communicated by the tribunes to the centurions and equites, and through the centurions and equites reached the soldiers at the proper time.

Guards, Sentinels, &c.— Out of the twenty maniples of Principes and Triarii in each legion, two were appointed to take charge of the broad passage or street called Principia, extending right across the camp in front of the tents of the tribunes. This being the place of general resort during the day, and, as we know from various sources, the part of the camp in which the altars and the eagles stood, great pains were taken that it should be kept perfectly clean and regularly watered, a labour which would fall very light when portioned out among four maniples.​a

Of the remaining eighteen maniples of Principes and Hastati in each legion, three were assigned by lot to each of the six tribunes, and of these three maniples one in turn rendered each day certain services to the tribune to whom it was specially attached. It took charge of his tent and baggage, saw that the former was properly pitched upon ground duly levelled all round, and protected the latter from damage or plunder. It also furnished two guards (φυλάκεια) of four men each, who kept watch, some in front of the tent and some behind, among the horses. We may remark in passing, that four was the regular number for a Roman guard (φυλάκειον); of these one always acted as sentinel, while the others enjoyed a certain degree of repose, ready, however, to start up at the first alarm. Compare the Acts of the Apostles, cap. xii παραδοὺς τέσσαρσι τετραδίοις στρατιωτῶν φυλάσσειν αὐτόν.

The Triarii were exempted from those duties imposed upon the Principes and Hastati, but each maniple of the Triarii furnished daily a guard of four men to that turma of the Equites which was quartered immediately behind them, in order to watch the horses, and to take care that they did not sustain any injury from getting entangled with their halters and heel ropes, or break loose and cause confusion and mischief.

One maniple was selected each day from the whole legionary force, to keep guard beside the tent of the general, that he might be secured alike from open danger and hidden treachery; this honourable task being devolved upon every maniple in rotation. Three sentinels were usually posted at the tents of the quaestor and of the legati; and by night sentinels kept watch at every maniple, being chosen out of the maniple which they guarded.

The Velites mounted guard by day and by night along the whole extent of the vallum: to them also in bodies of ten was committed the charge of the gates, while strong bodies of infantry and cavalry were thrown forward in advance of each gate, to resist any sudden onset, and give timely notice of the approach of the enemy.

Excubia; excubias agere; excubare; are the general terms used with reference to mounting guard whether by night or by day. Vigiliae; vigilias agere; vigilare; are restricted to night duty; Excubiae and Vigiliae frequently denoted not only the service itself, but also the individuals who performed it. Stationes is used specially to denote the advanced posts thrown forward in front of the gates, Custodes or Custodiae the parties who watched the gates themselves, Praesidia the sentinels on the ramparts, but all these words are employed in many other significations also.

Going the Rounds.— In order to ascertain the vigilance of the night sentinels (νυκτεριναὶ φυλαί) an ingenious scheme was devised. Each guard (φυλάκειον) consisted, as we have seen, of four men, and each of these in turn stood sentinel for one of the four watches into which the night was divided. The sentinels to whom it fell to go upon duty in the first watch, were conducted in the afternoon to the tent of the tribune by lieutenants of the maniples to which they belonged. Each of these men received from the tribune four small tokens (ξυλήφια), numbered from one to four for the four watches, and bearing also marks indicating the legion, and maniple or century from which the guard was taken. The individual who received these tokens retained the one which answered to his own watch, and distributed the rest among his three comrades. The duty of going the rounds (Vigilias circuire s. circumire, comp. Festus, s.v. fraxare) was committed to the Equites, and for this purpose each legion supplied daily four, picked out from each turma in rotation by the commander of the troop. The eight persons thus selected decided by lot in which watch they should make their rounds, two being assigned to each watch. They then repaired to the tribune, and each individual received a written order specifying the posts which he was to visit, every post being visited in each watch by one or other of the two to whom the watch belonged. They then repaired in a body to the first maniple of the Triarii, and there took up their quarters, because it was the duty of one of the centurions of that maniple to give notice of the commencement of each watch by a trumpet blast. At the appointed time each eques, accompanied by some friends, who acted as witnesses, visited all the posts named in his written order, from each sentinel whom he found on the alert he received one of the tokens described above, but if the sentinel was asleep or absent, then the eques of the rounds called upon his companions to witness the fact, and departed. The same process was followed by all the others, and on the following morning the officers of the rounds repaired to the tent of the tribune and delivered up the tokens. If the number of these was found to be complete, then all was well, but if any one was wanting, then it could be at once ascertained to what guard and to what watch the missing token belonged. The centurion of the company was ordered to bring forward the men implicated, and they were confronted the officer of the rounds. If the latter could prove by means of his witnesses, that he had actually visited the post in question, and found the sentinel asleep or absent, then the guilt of the sentinel could not be a matter of doubt; but if the officer failed to establish this, then the blame fell upon himself, and in either case the culprit was forthwith made over to a court martial. Sometimes we find centurions, tribunes, and even the general in change represented  p251 as going the rounds, but under ordinary circumstances, the duty was performed as we have described (Liv. XXII.1, XXVIII.24; Sall. Jug. 45; Tac. Hist. II.29.)

Watchword.— The watchword for the night was not communicated verbally, but by means of a small rectangular tablet of wood (πλατεῖον ἐπιγεγραμμένονtessera — to be carefully distinguished from the ξυλήφιον of the last paragraph), upon which it was written. One man was chosen out of each of those maniples and turmae which were quartered at that extremity of the lines most remote from the Principia. Each of these individuals (tesserarius) repaired towards sunset to the tent of the tribune, and received from him a tessera, on which the password and also a certain number or mark were inscribed. With this he returned to the maniple or turma to which he belonged, and taking witnesses, delivered it to the officer of the next adjoining maniple or turma, and he to the next until it had passed along the whole line, when it was returned by the person who received it last to the tribune. The regulation was that the whole of the tesserae should be restored before it was dark, and if any one was found wanting at the appointed time, the row to which it belonged could be at once discovered by means of the number or mark noticed above, an investigation took place at once into the cause of the delay, and punishment was inflicted upon the parties found to be in fault.

Not only mere passwords were circulated in this manner, but also, occasionally, general orders, as when we read in Livy, XXVII.46, "Tessera per castra ab Livio consule data erat, ut tribunum tribunus, centurio centurionem, eques equitem, pedes peditem acciperet."

Although the tesserarius received the tessera from the tribune, it proceeded in the first instance from the commander-in‑chief, as we may perceive from the passage just quoted, and many others. Under the empire it was considered the peculiar function of the prince to give the watchword to his guards (Tacit. Ann. I.7; comp. Suet. Claud. 42, Ner. 9).

I. Camp of Hyginus.

Passing over a space of about 250 years, we find ourselves amidst an order of things altogether new. The name Legiones still remains, but all the ancient divisions, with the exception of the Centuriae, have disappeared. The distribution of the soldiers into Velites, Hastati, Principes, and Triarii did not endure mon half a century after the era of Polybius; the organization by maniples was about the same period in a great measure superseded by the cohorts, and the cavalry were detached from the infantry and formed independent corps. In like manner the Socii, after the admission of the Italian states to the Roman franchise, ceased to form a separate class, and their place is now occupied by a motley crew of foreigners and barbarians serving in bands, designated by strange titles. We are reminded also that the republican form of government had given way to the dominion of a single individual by the appearance of a multitude of household troops and imperial body-guards, distinguished by various appellations, and invested with peculiar privileges. A complete Roman army did not now consist of Romanae Legiones cum Sociis, or of Legiones cum Sociis et Auxiliis, but of Legiones cum Supplementis, the term Supplementis including the whole of the various denominations alluded to above. In what follows, we shall attempt to delineate a summer camp (castra aestivalia), intended to contain three legions, with their supplements, a force, which in the time of Hyginus corresponded to the regular consular army of the sixth and seventh centuries of the city. It is but right, however, to call attention to the fact, that we do not here tread upon ground so firm as when Polybius was our guide. The text of Hyginus presents many difficulties and many corruptions; and there are not a few passages in which we are thrown too much upon conjecture. This, however, be it understood, applies almost exclusively to the minute details, for the general outline of the whole is clear and well ascertained. The plan sketched below, is taken almost entirely from Schelius, and the proportions of the different parts are carefully preserved. Omitting in this case the geometrical construction, we proceed at once to explain the figure.

The point from which the whole of the measurements proceeded is marked with a small cross, and was called Groma, that being the name of an instrument employed by surveyors, analogous, in its uses at least, to the modern cross staff, plane table and level.

The general form of the inclosure was an oblong, the two longer sides being at equal distances from the Groma, rounded off at the angles (angulos castrorum circinare oporter), 2320 feet in length by 1620 feet in breadth, the general rule being that the length should exceed the breadth by one third (castra in quantum fieri potuerit tertiata esse debebunt); when larger it was called Castra Classica, because, says Hyginus, the ordinary Buccinum or bugle could not be heard distinctly from one extremity to the other.

The Groma stood in the middle of the principal street (Via Principalis), which was sixty feet wide, extending right across the camp, with the two Portae Principales at its extremities. The two remaining gates, which, like the former, retained their ancient names, were the Porta Praetoria, which was nearest to the enemy (porta praetoria semper hostem spectare debet), and the Porta Decumana, and these were placed in the centre of the two shorter sides of the oblong. Immediately behind the Groma, a rectangular space, 720 feet long by 180 broad, was set apart for the emperor or commander-in‑chief, and, as in the consular camp, termed the Praetorium. Immediately behind the Praetorium, that is to say, at the extremity most distant from the Groma, a street called the Via Quintana, 40 feet wide, extended across the camp parallel to the Via Principalis. When the camp exceeded the ordinary dimensions, then two additional gates were formed at the extremities of the Via Quintana, the breadth of which was in that case increased to 50 feet.

It will be seen at a glance that the camp was divided into three segments by the Via Principalis and the Via Quintana. Each of these segments had a name. The whole of the middle segment, lying to the right and the left of the Praetorium,  p252 formed the Latera Praetorii. The segment included between the Via Principalis and that side of the camp in which the Porta Praetoria stood formed the Praetentura. The segment included between the Via Quintana and that side of the camp in which the Porta Decumana stood formed the Retentura.

The legiones being the most trustworthy of the troops in the provinces, were quartered by cohorts next to the rampart all round the camp, encircling completely with their lines the masses of foreigners, who, together with the imperial guards, formed the supplementa.

 p253  A clear space of 60 feet (intervallum) was left between the tents of the legionaries and the ramparts, and they were separated from the quarters of the other troops, whom they surrounded, by a street called the Via Sagularis, which ran completely round the camp, so that the whole of the legionaries, with the exception of the first cohort in each legion, and three ordinary cohorts for whom there is not room in the outer ring, were bounded on one side by the intervallum and on the other by the Via Sagularis. The remaining streets not particularly specified were comprehended under the general name Viae Vicinariae s. Vicinales, and their breadth was 20 feet.

The defences of a camp might be fourfold:— 1. Fossa. 2. Vallum. 3. Cervoli. 4. Arma.
1. The Fossa might be of two kinds, a. The Fossa fastigata, with both sides sloping, so as to form a wedge; or, b. the Fossa Punica, of which the outer side was perpendicular, the inner side sloping, as in the fossa fastigiata. The breadth in either case was to be at least 5 feet, but seem to have zzz feet. Outside of each gate a ditch was dug extending on both sides somewhat beyond the gate: this, on account of its shortness, was called Titulus, and in front of the titulus was a small semicircular redoubt (clavicula).
The Vallum was formed of earth and turf, or of stone, 6 feet in height, 8 feet broad.
When the nature of the ground did not admit of the construction of a sufficient vallum, then a cheval-de‑friseº (cervoli) was substituted.
When neither a Vallum nor Cervoli could be employed, then the camp was surrounded by a ring of armed men four deep, numerous sentries were posted in each line, and the cavalry patrolled in turn in every direction.

The words of Hyginus would lead us to suppose that when no danger was apprehended, a ditch alone was considered sufficient; and even this was excavated merely for the sake of exercising the men (causa disciplinae).

We can now proceed to point out in what manner the three segments were occupied, referring to the numbers on the figure, it being understood that, as before, we shall not enter here into any discussions regarding the origin and character of the different battalions named, all information upon such matters being given in the article Exercitus.

A. Praetorium et Latera Praetorii.

1. Praetorium. 2. Arae, on which public sacrifice was offered. The position assigned to them is conjectural; but they were, at all events, in the immediate vicinity of this spot. 3. Auguratorium, in which the Imperator took the auspices — the altars were perhaps erected in front of this place, at least such was the case sometimes (see Tacit. Ann. XV.30, where the form Augurale is employed). 4. Tribunal, the elevated platform from which addresses were delivered to the troops. Close to the praetorium was a guardhouse (stationi dari oportet secundum praetorium pedes viginti). 5. Comites Imperatoris, the personal staff of the Imperator, among whom the chief place, next to the Via Principalis, was assigned to the Praefectus Praetorio.º 6. Equites singulares Imperatoris et Equites Praetoriani: the number of these was variable; but Hyginus gives as an average 450 of the former and 400 of the latter. 7. Cohortes praetoriae quatuor. Primipilares. Evocati. Officiales. The praetorians were allowed twice as much space as the troops of the line. 8. Alae quingenariae quatuor. 9. In each of the spaces marked 9, on the extreme right and left of the Praetorium, bordering on the Via Sagularis (per rigorem viae sagularis) was placed the first cohort and the vexillarii of the remaining legion will be found in the Praetentura. The first cohort of a legion contained 960 men, being twice as numerous as the others; the vexillarii of a legion amounted to about 500.

B. Praetentura.

10. Scamnum Legatorum. The quarters of the legati. 11. Scamnum Tribunorum. Immediately behind the legati, were the legionary tribunes and the tribunes of the praetorian cohorts.

In the language of surveyors, scamnum was a rectangular figure, whose breadth exceeded its length, striga a rectangular figure, whose length exceeded its breadth. So, Signa and Tabulinum are the terms used with reference to the direction of the length and breadth respectively: thus, "Cohors prima causa signorum et aquilae intra viam sagulariam, et quoniam duplum numerum habet, duplam pedaturam accipiet, ut, puta, signis pedes centum viginti, tabulino pedes trecentos sexaginta, vel signis centum octoginta tabulino pedes ducentos quadraginta." It is the more necessary to call attention to this, because these significations have been passed over by the best lexicographers, and we find that some modern expounders of Hyginus imagine Tabulinum to have been an office where the books and accounts of the legion were kept.​b Another example of the use of these words will be given below.

12. Alae milliariae quatuor, one in each of these four compartments. 13. Valetudinarium, the hospital for the sick soldiers. 14. Veterinarium, the hospital for the sick horses. 15, 16. Classici, marines employed as pioneers. Mauri equites sexcenti. Pannonii Veredarii octingenti. These two bodies of light cavalry were quartered near the classici, because, when the latter were sent in advance to clear the way, they were guarded by the former. 17. Exploratores. General Roy in his plan places them in these two small compartments, but it appears more probable from the words of Hyginus, that they were quartered all together on the side next to 19. 18 and 19. The first cohort of the remaining legion and its Vexillarii.

On the opposite side of the Via Praetoria, three legionary cohorts, for whom there was not sufficient space outside of the Via Sagularis.

In the Praetentura stood also the Fabrica or workshop of the carpenters and armourers, erected at a distance from the Valetudinarium, so that the noise might not disturb the patients.

Within the scamnum of the legati were the Scholae of the first cohorts, the places apparently where the superior officers of the legions assembled in order to receive the general orders of the day.

C. Retentura.

20. Quaestorium. This space corresponded in name only with the Quaestorium of the Polybian camp, for it was no longer assigned to a quaestor (Quaestorium dicitur quod aliquando ibi quaestores pedaturam acceperint). It was occupied partly by prisoners of rank, hostages, and plunder, and here  p254 perhaps the Praefectus Castrorum may have been quartered, unless we are to look for him among the Comites Imperatoris.

21. Statorum centuriae duae, who guarded the rear of the praetorium, and always kept close to the person of the Imperator. These, like the praetorians, had double space assigned to them.

22. Cohortes equitatae milliariae duae. Cohortes equitatae quingenariae quatuor.

23. Cohortes peditatae milliariae tres. Cohortes peditatae quingenariae tres.

24. Nationes. Barbarian troops. Palmyreni quingenti. Gaetae nongenti. Daci septingenti. Britones quingenti. Cantabri septingenti. Among these we find enumerated Sumactares, a word which no one has succeeded in explaining, but it is in all probability a corrupt form.

Camels with their riders (cameli cum suis epibatis) were frequently included among the constituents of an army, being used both in offensive operations, and also in carrying plunder.

Two points strike us forcibly when we compare the camp of Hyginus with that of Polybius; first, the flimsy character of the fortifications, which must be attributed to the disinclination felt by the soldiers to perform regularly and steadily the same amount of labour which was cheerfully executed by soldiers of the republic; and, secondly, the desire every where visible to economise space, and compress every thing within the narrowest possible limits. Although the numbers of an army, such as we have been considering above, cannot be determined with absolute precision, they must, on the lowest computation, have exceeded 40,000 men, and these were crowded together into less than one half the space which they would have occupied according to the ancient system, the proportion of cavalry, moreover, being much larger in the imperial force. The camp of Polybius, calculated for less than 20,000, contains upwards of four millions of square feet, while the camp of Hyginus embraces little more than three millions and seven hundred thousand.

We may conclude with a few words upon a topic entirely passed over by Polybius, but on which Hyginus affords ample information in so far as the usages of his own day are concerned — the number and arrangement of the tents.

A double row of tents (papiliones) facing each other, with a space between for piling the arms of the soldiers, and for receiving the beasts of burden and the baggage, was termed Striga; a single row, with a corresponding space in front, Hemistrigium. The normal breadth of a Striga was 60 feet, of a Hemistrigium 30 feet, made up as follows:— 10 feet were allowed for the depth of each tent, 6 feet for a passage behind the tent, 5 feet for the arms piled in front of the tent, 9 feet for the jumenta and baggage; total 30 feet for the hemistrigium, which doubled for the striga gives 60, the space between the rows being 28 feet. The length of the striga or hemistrigium varied according to circumstances.

A full legionary century (plena centuria), when Hyginus wrote, consisted of 80 men, who occupied 10 papiliones. The length allowed for each papilio was 12 feet, 10 feet for the papilio itself, and 2 feet for lateral passages (incrementum tensurae), and thus the length of the line along which the papiliones of a century stretched was 10 × 12 - 120 feet. Out of this the centurion had a space allotted to him equal to that required for 2 tents, so that the privates of the century occupied 8 tents only, that is, they were quartered at the rate of 10 men to each tent. But since 16 men or 4 guards (τετραδία) in each century were always out upon duty, there were never more than 8 men actually in a tent at the same time.

Since a striga 120 feet in length and 60 feet in breadth, containing 7200 square feet, was allotted to 2 centuries, and since an ordinary legionary cohort contained 6 centuries, it follows that the space required for each cohort (pedatura cohortis) of 480 men was 21,600 square feet.

The troops were usually quartered in cohorts, and these might be variously disposed, it being always desirable that a whole century should always be ranged in an unbroken line.  p255 

If the striga was equal to one century in length, then the cohort would occupy three strigae in breadth, that is, a space 120 feet long, by 180 broad = 21,600 square feet. See fig. 6.

If the striga was equal in length to two centuries, then the cohort would occupy one whole striga and a hemistrigium, that is, a space 240 feet long by 90 feet broad = 21,600 square feet. See fig. 7.

If the striga was equal in length to three centuries, then the cohort would occupy one striga only, or a space 360 feet long by 60 feet broad = 21,600 square feet. See fig. 8.

It is to be observed that in the plan of the camp given above, the legionary cohorts on the longer sides are in strigae of 240 feet in length, those on the shorter sides in strigae of 360 feet in length.

When the number of legions in an army was greater in proportion to the supplementa than in the array which we have reviewed, then in order that they might still be ranged outside of the Via Sagularis, the strigae presented their breadth to the vallum instead of their length, or to use the technical phrase, the length which in the former case had been assigned to the Signa, was now given to the Tabulinum (Quodsi legiones plures acceperimus et supplementa pauciora ut necessarium sit cohortes circa vallum crebrius ponere convertemus pedaturam, quod fuerat signis tabulino dabimus).

If AB be the line of the vallum, C will represent the position of the cohort in the one case, D in the other.

Josephus, in his account of the Jewish war, takes special notice of the Roman encampments, and, although he does not enter into minute details, his observations, with which we shall conclude this article, form a useful supplement to Hyginus. It is evident from the numerous artizans for whom workshops are provided, from the towers with which the vallum was strengthened, and from the precaution of setting fire to every thing left behind, that the words of the historian refer chiefly to Castra Stativa. He begins by remarking (B. J. III.5) that the Romans when invading an enemy's country never hazard an engagement until they have fortified a camp (οὐ πρὶν ἅπτονται μάχης ἢ τειχίσαι στρατόπεδον), which, in form, is a square (διαμετρεῖται δὲ παρεμβολὴ τετράγμενος), with four gates, one on each side. The rampart by which it is surrounded exhibits the appearance of a wall furnished with towers at equal distances, and in the spaces between the towers is placed the artillery ready for immediate service (τούς τε ὀχυβελεῖς, καὶ καταπέλτας, καὶ λιθοβόλα, καὶ πὰν ἀφετήριον ὄργανον τιθέασιν, ἅπαντα πρὸς τὰς βολὰς ἕτοιμα). The camp is divided conveniently by streets, in the middle are the tents of the officers, and in the very centre of all the praetorium (τὸ στρατήγιον); there is also a forum (ἀγορά τις ἀποδείκνυται), and a place for artificers (χειροτέχναις χωρίον), of whom a great number follow the army with building tools, and seats for the tribunes and centurions (θωκοί τε λοχαιοῖς καὶ ταξίαρχαις), where they decide any disputes which may arise. When necessary (εἰ δὲ ἐπείγοι) a ditch is dug all round, four cubits deep and four cubits broad.

At day dawn (ὑπὸ δὲ τὴν ἕω) all the soldiers repair to the tents of their respective centurions (ἐπὶ τοὺς ἐκατοντάρχας) and salute them: the centurions repair to the tribunes (πρὸς τοὺς χιλιάρχους), along with whom all the centurionsº  p256 (ταξίαρχαι) repair to the commander-in‑chief, from whom they receive the watchword (σημεῖον) and the general orders of the day, to be conveyed by them to their respective divisions.

When a camp is broken up, at the first blast of the trumpet the soldiers strike the tents, and pack up the utensils; at the second they load the mules and other beasts of burden, set fire to every thing which could prove serviceable to an enemy, and stand like coursers ready to start forward on a race; the third gives the last warning that all things being now prepared every man must be in his place. Then the herald, standing at the right hand of general, demands thrice if they are ready for war, to which they all respond with loud and repeated cheers that they are ready, and for the most part, being filled with martial ardour, anticipate the question, and raise their right hands on high with a shout (B. J. III.5 §4).

Thayer's Notes:

a Maybe the principia were perfectly clean, but the ancients apparently just did not have the technology to keep the camp as a whole in a good state of hygiene. Our article omits any mention of latrines, but latrines there must have been, and with them, surely, the best precautions to maintain cleanliness; yet despite that, camps would have to be moved because of worsening sanitary conditions (Sallust, Jug. 44.5).

b Very probably by confusion with Tabularium.

[image ALT: Valid HTML 4.01.]

Page updated: 5 Apr 19