Having placed a standard on the spot on which they intend to put the Praetorium, they measure off a square round this standard, in such a way that each of its sides is a hundred feet from the standard, and the area of the square is four plethra.[297] Along one side of this square—whichever aspect appears most convenient for watering and foraging—the legions are stationed as follows. I have said that there were six Tribuni in each legion, and that each Consul had two legions,—it follows that there are twelve Tribuni in a Consular army. Well, they pitch the tents of these Tribuni all in one straight line, parallel to the side of the square selected, at a distance of fifty feet from it (there is a place too selected for the horses, beasts of burden, and other baggage of the Tribuni); these tents face the outer side of the camp and away from the square described above,—a direction which will henceforth be called “the front” by me. The tents of the Tribuni stand at equal distances from each other, so that they extend along the whole breadth of the space occupied by the legions.
[28.] From the line described by the front of these tents they measure another distance of a hundred feet towards the front. The principia. At that distance another parallel straight line is drawn, and it is from this last that they begin arranging the quarters of the legions, which they do as follows:—they bisect the last mentioned straight line and from that point draw another straight line at right angles to it; along this line, on either side of it facing each other, The quarters. the cavalry of the two legions are quartered with a space of fifty feet between them, which space is exactly bisected by the line last mentioned. The manner of encamping the infantry is similar to that of the cavalry. The whole area of each space occupied by the maniples and squadrons is a square, and faces the via;[298] the length facing the via is one hundred feet, and they generally try to make the depth the same, except in the case of the socii; and when they are employing legions of an extra number, they increase the length and depth of these squares proportionally.
[29.] The spaces assigned to the cavalry are opposite the space between the two groups of tents belonging to the Tribuni of the two legions, at right angles to the line along which they stand, like a cross-road; and indeed the whole arrangement of the viae is like a system of cross-roads, running on either side of the blocks of tents, those of the cavalry on one side and those of the infantry on the other. The spaces assigned to the cavalry and the Triarii in each legion are back to back, with no via between them, but touching each other, looking opposite ways; and the depth of the spaces assigned to the Triarii is only half that assigned to other maniples, because their numbers are generally only half; but though the number of the men is different, the length of the space is always the same owing to the lesser depth. Next, parallel with these spaces, at a distance of fifty feet, they place the Principes facing the Triarii; and as they face the space between themselves and the Triarii, we have two more roads formed at right angles to the hundred-foot area in front of the tents of the Tribunes, and running down from it to the outer agger of the camp on the side opposite to that of the Principia, which we agreed to call the front of the camp. Behind the spaces for the Triarii and looking in the opposite direction, and touching each other, are the spaces for the Hastati. These several branches of the service (Triarii, Principes, Hastati), being each divided into ten maniples, the cross-roads between the blocks are all the same length and terminate in the front agger of the camp; towards which they cause the last maniples in the rows to face.
[30.] Beyond the Hastati they again leave a space of fifty feet, and there, beginning from the same base (the Principia), and going in a parallel direction, and to the same distance as the other blocks, they place the cavalry of the allies facing the Hastati. Now the number of the allies, as I have stated above, is equal to that of the legions in regard to the infantry, though it falls below that if we omit the extraordinarii; but that of the cavalry is double, when the third part is deducted for service among the extraordinarii. Therefore in marking out the camp the spaces assigned to the latter are made proportionally deeper, so that their length remains the same as those occupied by the legions. Thus five viae are formed:[299] and back to back with these cavalry are the spaces for the infantry of the allies, the depth being proportionally increased according to their numbers;[300] and these maniples face the outer sides of the camp and the agger. In each maniple the first tent at either end is occupied by the centurions. Between the fifth and sixth squadrons of cavalry, and the fifth and sixth maniple of infantry, there is a space of fifty left, Via Quintana. so that another road is made across the camp at right angles to the others and parallel to the tents of the Tribuni, and this they call the Via Quintana, as it runs along the fifth squadrons and maniples.
[31.] The space behind the tents of the Tribuni is thus used. On one side of the square of the Praetorium is the market, The space between the Principia and the agger. on the other the office of the Quaestor and the supplies which he has charge of. Then behind the last tent of the Tribuni on either side, arranged at right angles to those tents, are the quarters of the cavalry picked out of the extraordinarii, as well as of some of those who are serving as volunteers from personal friendship to The Staff, or Praetoria cohors.Consuls. All these are arranged parallel to the side aggers, facing on the one side the Quaestorium, on the other the market-place. And, generally speaking, it falls to the lot of these men not only to be near the Consul in the camp, but to be wholly employed about the persons of the Consul and the Quaestor on the march and all other occasions. Back to back with these again, facing the agger, are placed the infantry who serve in the same way as these cavalry.[301]
Beyond these there is another empty space or road left, one hundred feet broad, parallel to the tents of the Tribuni, skirting the market-place, Praetorium, and Quaestorium, from agger to agger. On the further side of this road the rest of the equites extraordinarii are placed facing the market-place and Quaestorium: and between the quarters of these cavalry of the two legions a passage is left of fifty feet, exactly opposite and at right angles to the square of the Praetorium, leading to the rearward agger.
Back to back with the equites extraordinarii are the infantry of the same, facing the agger at the rear of the whole camp. And the space left empty on either side of these, facing the agger on each side of the camp, is given up to foreigners and such allies as chance to come to the camp.
The result of these arrangements is that the whole camp is a square, with streets and other constructions regularly planned like a town. The space round the quarters. Between the line of the tents and the agger there is an empty space of two hundred feet on every side of the square, which is turned to a great variety of uses. To begin with, it is exceedingly convenient for the marching in and out of the legions. For each division descends into this space by the via which passes its own quarters, and so avoids crowding and hustling each other, as they would if they were all collected on one road. Again, all cattle brought into the camp, as well as booty of all sorts taken from the enemy, are deposited in this space and securely guarded during the night-watches. But the most important use of this space is that, in night assaults, it secures the tents from the danger of being set on fire, and keeps the soldiers out of the range of the enemy’s missiles; or, if a few of them do carry so far, they are spent and cannot penetrate the tents.
[32.] The number then of foot-soldiers and cavalry being given (at the rate, that is to say, of four thousand or of five thousand for each legion), Provision for extra numbers, and the length, depth, and number of the maniples being likewise known, as well as the breadth of the passages and roads, it becomes possible to calculate the area occupied by the camp and the length of the aggers. If on any occasion the number of allies, either those originally enrolled or those who joined subsequently, exceeds their due proportion, the difficulty is provided for in this way. To the overplus of allies who joined subsequent to the enrolment of the army are assigned the spaces on either side of the Praetorium, the market-place and Quaestorium being proportionally contracted. For the extra numbers of allies who joined originally an extra line of tents (forming thus another via) is put up parallel with the other tents of the socii, facing the agger on either side of the camp. and for two consular armies. But if all four legions and both Consuls are in the same camp, all we have to do is to imagine a second army, arranged back to back to the one already placed, in exactly the same spaces as the former, but side by side with it at the part where the picked men from the extraordinarii are stationed facing the rearward agger. In this case the shape of the camp becomes an oblong, the area double, and the length of the entire agger half as much again. This is the arrangement when both Consuls are within the same agger; but if they occupy two separate camps, the above arrangements hold good, except that the market-place is placed half way between the two camps.