The Histories of Polybius, Vol. 1 (of 2)

by Polybius

ON THE ART OF COMMANDING ARMIES

[12.] The chances and accidents that attend military expeditions require great circumspection; and it is possible to provide for all of them with precision, provided that a man gives his mind to the conduct of his plan of campaign. Now that fewer operations in war are carried out openly and by mere force, than by stratagem and the skillful use of opportunity, any one that chooses may readily learn from the history of the past. And again that operations depending on the choice of opportunity oftener fail than succeed is easily proved from experience. Nor can there be any doubt that the greater part of such failures are due to the folly or carelessness of the leaders. It is time therefore to inquire into the rules of this art of strategy.

Such things as occur in campaigns without having been calculated upon in any way we must not speak of as operations, but as accidents or casualties. It is the conduct of a campaign in accordance with an exact plan that I am to set forth: omitting all such things as do not fall under a scientific rule, and have no fixed design.

[13.] Every operation requires a time fixed for its commencement, a period and place for its execution, The points of inherent importance in the conduct of a campaign,—time, place, secrecy, code of signals, agents, and method. secrecy, definite signals, persons by whom and with whom it is to be executed, and a settled plan for conducting it. It is evident that the man who has rightly provided for each of these details will not fail in the ultimate result, while he who has neglected any single one of them will fail in the whole. Such is the order of nature, that one insignificant circumstance will suffice for failure, while for success rigid perfection of every detail is barely enough.

Leaders then should neglect no single point in conducting such expeditions.

Now the head and front of such precautions is silence; and not to allow either joy at the appearance of an unexpected hope, or fear, or familiarity, Things necessary. 1. Silence. or natural affection, to induce a man to communicate his plans to any one unconcerned, but to impart it to those and those alone without whom it is impossible to complete his plan, and not even to them a moment sooner than necessary, but only when the exigencies of the particular service make it inevitable. It is necessary, moreover, not only to be silent with the tongue, but much more so in the mind. For it has happened to many generals before now, while preserving an inviolable silence, to betray their thoughts either by the expression of their countenances or by their actions.

The second requisite is to know accurately the conditions under which marches by day or night may be 2. Knowledge of the capabilities of the force in moving. performed, and the distances to which they can extend, and not only marches on land, but also voyages by sea.

The third and most important is to have some knowledge of the seasons, and to be able to adapt the design to them.

Nor again is the selection of the ground for the operation to be regarded as unimportant, since it often happens that it is this which makes what seems impossible possible, and what seemed possible impossible.

3. Care in concerting signals.
4. Care in selecting men.Finally there must be no neglect of the subject of signals and counter signals; and the choice of persons by whom and with whom the operation is to be carried out.

[14.] Of these points some are learnt by experience, some from history, and others by the study of scientific strategy. 5. Knowledge of localities. It is a most excellent thing too that the general should have a personal knowledge both of the roads, and the locality which he has to reach, and its natural features, as well as of the persons by whom and with whom he is to act. If that is not possible, the next best thing is that he should make careful inquiries and not trust just any one: and men who undertake to act as guides to such places should always deposit security with those whom they are conducting.

These, and other points like them, it is perhaps possible that leaders may learn sufficiently from the mere study of strategy, 6. Accurate knowledge of natural phenomena enabling a general to make accurate calculation of time. whether practical or in books. But scientific investigation requires scientific processes and demonstrations, especially in astronomy and geometry; the working out of which is not much to our present point, though their results are important, and may contribute largely to the success of such undertakings.

The most important operation in astronomy is the calculation of the lengths of the days and nights. If these had been uniform it would not have been a matter requiring any study, but the knowledge would have been common to all the world: since however they not only differ with each other but also with themselves, it is plainly necessary to be acquainted with the increase and diminution of both the one and the other. How can a man calculate a march, and the distance practicable in a day or in a night, if he is unacquainted with the variation of these periods of time? In fact nothing can be done up to time without this knowledge,—it is inevitable otherwise that a man should be sometimes too late and sometimes too soon. And these operations are the only ones in which being too soon is a worse fault than being too late. For the general who overstays the proper hour of action only misses his chance, since he can find out that he has done so before he arrives, and so get off safely: but he that anticipates the hour is detected when he comes up; and so not only misses his immediate aim, but runs a risk of ruining himself altogether.

[15.] In all human undertakings opportuneness is the most important thing, but especially in operations of war. Therefore a general must have at his fingers’ ends the season of the summer and winter solstice, the equinoxes, and the periods between them in which the days and nights increase and diminish. For it is by this knowledge alone that he can compute the distance that can be done whether by sea or land. Again, he must necessarily understand The divisions of the day; the subdivisions both of the day and the night, in order to know at what hour to order the reveillé, or the march out; for the end cannot be attained unless the beginning be rightly taken. As for the periods of the day, they may be observed by the shadows or by the sun’s course, and the quarter of the heaven in which it has arrived, but it is difficult to do the same for the night, unless a man is familiar with the phenomenon of the twelve signs of the Zodiac, of the night. and their law and order: and this is easy to those who have studied astronomy. For since, though the nights are unequal in length, at least six of the signs of the Zodiac are nevertheless above the horizon every night, it is plain that in the same portions of every night equal portions of the twelve signs of the Zodiac rise. Now as it is known what portion of the sphere is occupied by the sun during the day, it is evident that when he has set the arc subtended by the diameter of his arc must rise. Therefore the length of the night is exactly commensurate with the portion of the Zodiac which appears above the horizon after sunset. And, given that we know the number and size of the signs of the Zodiac, the corresponding divisions of the night are also known. If however the nights be cloudy, the moon must be watched, since owing to its size its light as a general rule is always visible, at whatsoever point in the heaven it may be. The hour may be guessed sometimes by observing the time and place of its rising, or again of its setting, if you only have sufficient acquaintance with this phenomenon to be familiar with the daily variation of its rising. And the law which it too follows admits of being easily observed; for its revolution is limited by the period of one month, which serves as a model to which all subsequent revolutions conform.

[16.] And here one may mention with admiration that Homer represents Ulysses, that truest type of a leader of men, The example of Ulysses. See Odyss. 5, 270 sq. taking observations of the stars, not only to direct his voyages, but his operations on land also. For such accidents as baffle expectation, and are incapable of being accurately reckoned upon, are quite sufficient to bring us to great and frequent distress, for instance, downpours of rain and rise of torrents, excessive frosts and snows, misty and cloudy weather, and other things like these;—but if we also neglect to provide for those which can be foreseen, is it not likely that we shall have ourselves to thank for frequent failures? None of these means then must be neglected, if we wish to avoid those errors into which many others are said to have fallen, as well as the particular generals whom I am about to mention by way of examples.

[17.] When Aratus, the Strategus of the Achaean league, attempted to take Cynaetha by treachery, Aratus fails at Cynaetha. he arranged a day with those in the town who were co-operating with him, on which he was to arrive on the banks of the river which flows past Cynaetha, and to remain there quietly with his forces: while the party inside the town about midday, when they got an opportunity, were to send out one of their men quietly, wrapped in a cloak, and order him to take his stand upon a tomb agreed upon in front of the city; the rest were to attack the officers who were accustomed to guard the gate while taking their siesta. This being done, the Achaeans were to rise from their ambush and to make all haste to occupy the gate. These arrangements made, and the time having come, Aratus arrived; and having concealed himself down by the river, waited there for the signal. But about an hour before noon, a man, whose profession it was to keep a fine kind of sheep near the town, wishing to ask some business question of the shepherd, came out of the gate with his cloak on, and standing upon the same tomb looked round to find the shepherd. Whereupon Aratus, thinking that the signal had been given, hurried with all his men as fast as he could towards the gate. But the gate being hurriedly closed by the guard, owing to no preparations having yet been made by the party in the town, the result was that Aratus not only failed in his attempt but was the cause of the worst misfortunes to his partisans. For being thus detected they were dragged forward and put to death. What is one to say was the cause of this catastrophe? Surely that the general arranged only for a single signal, and being then quite young had no experience of the accuracy secured by double signals and counter-signals. On so small a point in war does the success or failure of an operation turn.

[18.] Again the Spartan Cleomenes, when proposing to take Megalopolis by a stratagem, arranged with the Cleomenes. See 2, [55]. guards of that part of the wall near what is called the Cavern to come out with all their men in the third watch, the hour at which his partisans were on duty on the wall; but not having taken into consideration the fact that at the time of the rising of the Pleiads the nights are very short, May 12.he started his army from Sparta about sunset. The result was that he was not able to get there in time, but being overtaken by daybreak, made a rash and ill-considered attempt to carry the town, and was repulsed with considerable loss and the danger of a complete overthrow. Now if he had, in accordance with his arrangement, hit the proper time, and led in his men while his partisans were in command of the entrance, he would not have failed in his attempt.

Similarly, once more, King Philip, as I have already stated, when carrying on an intrigue in the city of Meliteia, Philip’s attack on Meliteia. See 5, [97]. made a mistake in two ways. The ladders which he brought were too short for their purpose, and he mistook the time. For having arranged to arrive about midnight, when every one was fast asleep, he started from Larissa and arrived in the territory of Meliteia too early, and was neither able to halt, for fear of his arrival being announced in the city, nor to get back again without being discovered. Being compelled therefore to continue his advance, he arrived at the city while the inhabitants were still awake. Consequently he could neither carry the wall by an escalade, because of the insufficient length of the ladders; nor enter by the gate, because it was too early for his partisans inside to help him. Finally, he did nothing but irritate the people of the town, and, after losing a considerable number of his own men, retired unsuccessful and covered with disgrace; having only given a warning to the rest of the world to distrust him and be on their guard against him.

[19.] Again Nicias, the general of the Athenians, had it in his power to have saved the army besieging Syracuse, Nicias, B.C. 413. Thucyd. 7, 50.and had selected the proper time of the night for escaping the observation of the enemy, and retiring to a place of safety. And then because the moon was eclipsed, regarding it superstitiously as of evil portent, he stopped the army from starting. Thanks to this it came about that, when he started the next day, the enemy had obtained information of his intention, and army and generals alike fell into the hands of the Syracusans. Yet if he had asked about this from men acquainted with such phenomena, he might not only have avoided missing his opportunity for such an absurd reason, but have also used the occurrence for his own benefit owing to the ignorance of the enemy. For the ignorance of their neighbours contributes more than anything else to the success of the instructed.

Such then are examples of the necessity of studying celestial phenomena. But as for securing the proper length of scaling ladders, The method of judging of the length necessary for scaling ladders. the following is the method of making the calculation. Suppose the height of the wall to be given by one of the conspirators within, the measurement required for the ladders is evident; for example, if the height of the wall is ten feet or any other unit, the ladders must be full twelve; and the interval between the wall and the foot of the ladder must be half the length of the ladder, that the ladders may not break under the weight of those mounting if they are set farther away, nor be too steep to be safe if set nearer the perpendicular. But supposing it not to be possible to measure or get near the wall: the height of any object which rises perpendicularly on its base can be taken by those who choose to study mathematics.

[20.] Once more, therefore, those who wish to succeed in military projects and operations must have studied geometry, not with professional completeness, but far enough to have a comprehension of proportion and equations. For it is not only in such cases that these are necessary, but also for raising the scale of the divisions of a camp. For sometimes the problem is to change the entire form of the camp, and yet to keep the same proportion between all the parts included: at other times to keep the same shape in the parts, and to increase or diminish the whole area on which the camp stands, adding or subtracting from all proportionally. On which point I have already spoken in more elaborate detail in my Notes on Military Tactics. For I do not think that any one will reasonably object to me that I add a great burden to strategy, in urging on those who endeavour to acquire it the study of astronomy and geometry: for, while rather rejecting all that is superfluous in these studies, and brought in for show and talk, as well as all idea of enjoining their prosecution beyond the point of practical utility, I am most earnest and eager for so much as is barely necessary. For it would be strange if those who aim at the sciences of dancing and flute-playing should study the preparatory sciences of rhythms and music, (and the like might be said of the pursuits of the palaestra), from the belief that the final attainment of each of these sciences requires the assistance of the latter; while the students of strategy are to feel aggrieved if they find that they require subsidiary sciences up to a certain point. That would mean that men practising common and inferior arts are more diligent and energetic than those who resolve to excel in the best and most dignified subject, which no man of sense would admit....