Flavius Vegetius Renatus

Military Matters

The Text is written in 390 A.D. British translation published in 1767. Vegetius provides a detailed description of military equipment, organization and practice and is thus an invaluable source for Roman military history.

Here some interesting part of the book:


The line of infantry being formed, the cavalry are drawn up in the wings. The heavy horse, that is, the cuirassiers and troopers armed with lances, should join the infantry. The light cavalry, consisting of the archers and those who have no cuirasses, should be placed at a greater distance. The best and heaviest horse are to cover the flanks of the foot, and the light horse are posted as abovementioned to surround and disorder the enemy's wings. A general should know what part of his own cavalry is most proper to oppose any particular squadrons or troops of the enemy. For from some causes not to be accounted for some particular corps fight better against others, and those who have defeated superior enemies are often overcome by an inferior force.
If your cavalry is not equal to the enemy's it is proper, after the ancient custom, to intermingle it with light infantry armed with small shields and trained to this kind of service. By observing this method, even though the flower of the enemy's cavalry should attack you, they will never be able to cope with this mixed disposition. This was the only resource of the old generals to supply the defects of their cavalry, and they intermingled the men, used to running and armed for this purpose with light shields, swords and darts, among the horse, placing one of them between two troopers.

The method of having bodies of reserves in rear of the army, composed of choice infantry and cavalry, commanded by the supernumerary lieutenant generals, counts and tribunes, is very judicious and of great consequence towards the gaining of a battle. Some should be posted in rear of the wings and some near the center, to be ready to fly immediately to the assistance of any part of the line which is hard pressed, to prevent its being pierced, to supply the vacancies made therein during the action and thereby to keep up the courage of their fellow soldiers and check the impetuosity of the enemy. This was an invention of the Lacedaemonians, in which they were imitated by the Carthaginians. The Romans have since observed it, and indeed no better disposition can be found.
The line is solely designed to repulse, or if possible, break the enemy. If it is necessary to form the wedge or the pincers, it must be done by the supernumerary troops stationed in the rear for that purpose. If the saw is to be formed, it must also be done from the reserves, for if once you begin to draw off men from the line you throw all into confusion. If any flying platoon of the enemy should fall upon your wing or any other part of your army, and you have no supernumerary troops to oppose it or if you pretend to detach either horse or foot from your line for that service by endeavoring to protect one part, you will expose the other to greater danger. In armies not very numerous, it is much better to contract the front, and to have strong reserves. In short, you must have a reserve of good and well-armed infantry near the center to form the wedge and thereby pierce the enemy's line; and also bodies of cavalry armed with lances and cuirasses, with light infantry, near the wings, to surround the flanks of the enemy.


The post of the commander-in-chief is generally on the right between the cavalry and infantry. For from this place he can best direct the motions of the whole army and move elements with the greatest ease wherever he finds it necessary. It is also the most convenient spot to give his orders to both horse and foot and to animate them equally by his presence. It is his duty to surround the enemy's left wing opposed to him with his reserve of horse and light infantry, and attack it in the flank and rear. The second in command is posted in the center of the infantry to encourage and support them. A reserve of good and well-armed infantry is near him and under his orders. With this reserve he either forms the wedge to pierce the enemy's line or, if they form the wedge first, prepares the pincers for its reception. The post of the third in command is on the left. He should be a careful and intrepid officer, this part of the army being difficult to manage and defective, as it were, from its situation in the line. He should therefore have a reserve of good cavalry and active infantry to enable him always to extend his left in such a manner as to prevent its being surrounded.
The war shout should not be begun till both armies have joined, for it is a mark of ignorance or cowardice to give it at a distance. The effect is much greater on the enemy when they find themselves struck at the same instant with the horror of the noise and the points of the weapons.
You must always endeavor to get the start of your enemy in drawing up in order of battle, as you will then have it in your power to make your proper dispositions without obstruction. This will increase the courage of your own troops and intimidate your adversaries. For a superiority of courage seems to be implied on the side of an army that offers battle, whereas troops begin to be fearful who see their enemies ready to attack them. You will also secure another great advantage, that of marching up in order and falling upon them while forming and still in confusion. For part of the victory consists in throwing the enemy into disorder before you engage them.

An able general never loses a favorable opportunity of surprising the enemy either when tired on the march, divided in the passage of a river, embarrassed in morasses, struggling with the declivities of mountains, when dispersed over the country they think themselves in security or are sleeping in their quarters. In all these cases the adversaries are surprised and destroyed before they have time to put themselves on their guard. But if they are too cautious to give you an opportunity of surprising or ensnaring them, you are then obliged to engage openly and on equal terms. This at present is foreign to the subject. However military skill is no less necessary in general actions than in carrying on war by subtlety and stratagem.
Your first care is to secure your left wing from being surrounded by the enemy's numbers or attacked in flank or rear by flying platoons, a misfortune that often happens. Nor is your right to be neglected, though less frequently in danger. There is only one remedy for this: to wheel back your wing and throw it into a circular position. By this evolution your soldiers meet the enemy on the quarter attacked and defend the rear of their comrades. But your best men should be posted on the angles of the flanks, since it is against them the enemy make their principal efforts.
There is also a method of resisting the wedge when formed by the enemy. The wedge is a disposition of a body of infantry widening gradually towards the base and terminating in a point towards the front. It pierces the enemy's line by a multitude of darts directed to one particular place. The soldiers call it the swine's head. To oppose this disposition, they make use of another called the pincers, resembling the letter V, composed of a body of men in close order. It receives the wedge, inclosing it on both sides, and thereby prevents it from penetrating the line.
The saw is another disposition formed of resolute soldiers drawn up in a straight line advanced into the front against the enemy, to repair any disorder. The platoon is a body of men separated from the line, to hover on every side and attack the enemy wherever they find opportunity. And against this is to be detached a stronger and more numerous platoon.
Above all, a general must never attempt to alter his dispositions or break his order of battle during the time of action, for such an alteration would immediately Occasion disorder and confusion which the enemy would not fail to improve to their advantage.

An army may be drawn up for a general engagement in seven different formations. The first formation is an oblong square of a large front, of common use both in ancient and modern times, although not thought the best by various judges of the service, because an even and level plain of an extent sufficient to contain its front cannot always be found, and if there should be any irregularity or hollow in the line, it is often pierced in that part. Besides, an enemy superior in number may surround either your right or left wing, the consequence of which will be dangerous, unless you have a reserve ready to advance and sustain his attack. A general should make use of this disposition only when his forces are better and more numerous than the enemy's, it being thereby in his power to attack both the flanks and surround them on every side.
The second and best disposition is the oblique. For although your army consists of few troops, yet good and advantageously posted, it will greatly contribute to your obtaining the victory, notwithstanding the numbers and bravery of the enemy. It is as follows: as the armies are marching up to the attack, your left wing must be kept back at such a distance from the enemy's right as to be out of reach of their darts and arrows. Your right wing must advance obliquely upon the enemy's left, and begin the engagement. And you must endeavor with your best cavalry and infantry to surround the wing with which you are engaged, make it give way and fall upon the enemy in the rear. If they once give ground and the attack is properly seconded, you will undoubtedly gain the victory, while your left wing, which continued at a distance, will remain untouched. An army drawn up in this manner bears some resemblance to the letter A or a mason's level. If the enemy should be beforehand with you in this evolution, recourse must be had to the supernumerary horse and foot posted as a reserve in the rear, as I mentioned before. They must be ordered to support your left wing. This will enable you to make a vigorous resistance against the artifice of the enemy.
The third formation is like the second, but not so good, as it obliges you to begin the attack with your left wing on the enemy's right. The efforts of soldiers on the left are weak and imperfect from their exposed and defective situation in the line. I will explain this formation more clearly. Although your left wing should be much better than your right, yet it must be reinforced with some of the best horse and foot and ordered to commence the acnon with the enemy's right in order to disorder and surround it as expeditiously as possible. And the other part of your army, composed of the worst troops, should remain at such a distance from the enemy's left as not to be annoyed by their darts or in danger of being attacked sword in hand. In this oblique formation care must be taken to prevent the line being penetrated by the wedges of the enemy, and it is to be employed only when the enemy's right wing is weak and your greatest strength is on your left.
The fourth formation is this: as your army is marching to the attack in order of battle and you come within four or five hundred paces of the enemy, both your wings must be ordered unexpectedly to quicken their pace and advance with celerity upon them. When they find themselves attacked on both wings at the same time, the sudden surprise may so disconcert them as to give you an easy victory. But although this method, if your troops are very resolute and expert, may ruin the enemy at once, yet it is hazardous. The general who attempts it is obliged to abandon and expose his center and to divide his army into three parts. If the enemy are not routed at the first charge, they have a fair opportunity of attacking the wings which are separated from each other and the center which is destitute of assistance.
The fifth formation resembles the fourth but with this addition: the light infantry and the archers are formed before the center to cover it from the attempts of the enemy. With this precaution the general may safely follow the above mentioned method and attack the enemy's left wing with his right, and their right with his left. If he puts them to flight, he gains an immediate victory, and if he fails of success his center is in no danger, being protected by the light infantry and archers.
The sixth formation is very good and almost like the second. It is used when the general cannot depend either on the number or courage of his troops. If made with judgment, notwithstanding his inferiority, he has often a good chance for victory. As your line approaches the enemy, advance your right wing against their left and begin the attack with your best cavalry and infantry. At the same time keep the rest of the army at a great distance from the enemy's right, extended in a direct line like a javelin. Thus if you can surround their left and attack it in flank and rear, you must inevitably defeat them. It is impossible for the enemy to draw off reinforcements from their right or from their center to sustain their left in this emergency, since the remaining part of your army is extended and at a great distance from them in the form of the letter L. It is a formation often used in an action on a march.
The seventh formation owes its advantages to the nature of the ground and will enable you to oppose an enemy with an army inferior both in numbers and goodness, provided one of your flanks can be covered either with an eminence, the sea, a river, a lake, a city, a morass or broken ground inaccessible to the enemy. The rest of the army must be formed, as usual, in a straight line and the unsecured flank must be protected by your light troops and all your cavalry. Sufficiently defended on one side by the nature of the ground and on the other by a double support of cavalry, you may then safely venture on action.
One excellent and general rule must be observed. If you intend to engage with your right wing only, it must be composed of your best troops. And the same method must be taken with respect to the left. Or if you intend to penetrate the enemy's line, the wedges which you form for that purpose before your center, must consist of the best disciplined soldiers. Victory in general is gained by a small number of men. Therefore the wisdom of a general appears in nothing more than in such choice of disposition of his men as is most consonant with reason and service.


Download books I, II and III by Flavius Vegetius Renatus
(Book IV handles about sieges and naval combat)

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