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Four The Date of the Dema Wall
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Contemporary Principles of Territorial Defense

The appropriateness of the Dema wall to the defensive principles of the time of the Boiotian War has already been partially demonstrated through the comparison in chapter 2 of the Dema to the Theban stockade and to other works associated with Chabrias. The demonstration is complete when it is seen how well the Dema system exemplifies the precepts of defensive planning found in the writings of Aeneas Tacticus, Xenophon, and Plato, all of whom were practitioners or observers of military science at the time of the Boiotian War, and all of whom wrote within a generation of the end of that war.

The most derailed extant fourth-century handbook on defensive preparations, and the one most relevant to our purposes, is the work by Aeneas Tacticus.[15] In this treatise, Aeneas is chiefly concerned with how a commander should prepare the defenses of a city at war which was liable to undergo a siege, but he also devotes attention to the problem of repulsing an attacking army in the field before the city itself is invested. Aeneas' precepts in this connection concern just the sort of circumstances that must have occasioned the construction of the Dema wall, namely, a "war crisis and a threat of invasion."

Under normal circumstances, Aeneas expects defending forces to be assembled only when the approach of the enemy is announced by messenger or by signal. Since the invading army must come in sufficient strength to overwhelm the defenders in pitched battle, Aeneas advises the defending commander to "attack the enemy where you are not unwilling to do battle, and where you will not be at a disadvantage in the fight."[16] This means that under most conditions, the defending commander will have to allow the enemy to proceed with his plundering until the opportune moment or place for a counterattack is reached. Only where the terrain of the frontier is suitable does Aeneas suggest that advance preparations might be effective in keeping an invading army out of the countryside altogether:


And should the countryside not be easy to invade, but have few and narrow passes into it, you must prepare these in advance, distributing forces as has already been described, in order to oppose at the passes those who are attacking and planning to march upon the city, while men who can communicate by signal fires the fortunes of each division are already in position, so that these divisions can bring support, if in any way they need one another's help.[17]

The distribution of forces referred to by Aeneas involves the occupation of high ground by light troops, the use of cavalry patrols, the preparation of ambushes, and the positioning of bodies of hoplite troops where they can advance to support those who engage the enemy first.[18] The building of fieldworks might be among the preparations that Aeneas has in mind, although he does not specifically mention such here. Separate divisions of defending forces will have to prepare themselves at appropriate points along each of the approaches, and a signal system must be established so that any one division under attack can be sup-ported by the others as needed. As Aeneas recognizes, such preparations are viable only if the defensive positions can be few and strong:

Otherwise, if the countryside should not be difficult to invade, but it is possible for large forces to invade at many points, you must occupy advantageous places in the countryside so as to make it difficult for the enemy to advance upon the city. But if there are no such places, you must occupy whatever positions near the city are useful for fighting at an advantage while allowing you to retire at ease whenever you wish to withdraw to the city.[19]

For Aeneas, topography above all dictates the actions to be taken by defenders facing a full-scale invasion.[20] The particular composition and


relative strengths of the opposing armies are not of central importance in Aeneas' reckoning because these factors are predictable, within broad limits, and can be taken for granted. The invaders will have a strong army, numerically superior to the defenders, while the defenders themselves will have an army of some size (possibly including allies and mercenaries) that is made up of appropriate proportions of heavy and light infantry and cavalry.[21] Within this general framework, and given the fore-thought that Aeneas' writings were meant to inspire in a commander, the defenders' strategy would be largely determined by the opportunities afforded by local terrain.

The essence of Aeneas' advice on the defense of territory is that an invading army can be halted only where the defenders can occupy strong ground along the invader's route, compelling the enemy to give battle on terms advantageous to the defenders. Aeneas assumes that narrow passes might provide defensive positions strong enough that even a division of the defending force could hold off the entire invading army, although any division sent to guard a pass before the arrival of the enemy will probably have to be reinforced when a direct assault on its position appears imminent. In general, a committed stand can be made only where the defenders are reasonably sure that the enemy cannot circumvent their position and cut them off from their own city. So wherever more than one pass must be guarded, the defending commander must judge the risks of being outmanuvered by the enemy, who might attack at several points, against the strengths of his own positions in determining whether or not to allow his forces to give way before the enemy and in deciding where to commit his main strength to battle.

The defensive strategy underlying the placement of the Dema wall and the various watchtowers in communication with it, as discussed in the first section of this chapter, accords very well with these precepts. Given the large extent of Attic territory, and especially the complexity of the topography toward the Megarian frontier, the Aigaleos-Parnes gap is indeed the most advantageous point to occupy in anticipation of an enemy,

.[22] The fact that Aeneas does not specifically mention the preparation of fieldworks like the Dema is no objection to seeing such tactical devices employed in his scheme. We know that such fieldworks were used in his day, and it is quite possible that Aeneas did discuss them elsewhere, in writings which have not survived.[23]


Xenophon discusses the defensibility of Attica in terms that correspond with significant aspects of Aeneas' advice and with the strategy evident in the Dema wall. In the dialogue from the Memorabilia quoted at the beginning of chapter 1, Xenophon notes that "great mountains reaching Boiotia protect our country, through which the passes are narrow and steep, and  . . . the interior of our country is divided by sheer mountains."[24] The light troops that should hold these mountains for the Athenians, according to Xenophon, were essentially those ephebes and peripoloi who did in fact guard Attic strongholds and patrol the frontiers to protect Attic land from minor raids and depredations by the Boiotians, whose animosity posed a constant threat to the Athenians during the 360s and 350s, when this passage was written.[25] But the passage is also evocative of the light troops who guarded these passes in 378-375, beginning with those under Chabrias at Eleutherai in the winter of 379/8 and culminating with those who repelled the forces of Kleombrotos on Kithairon in 376.[26]

It is especially relevant to note Xenophon's reference in this context to the mountain barriers in the interior of Attica which, when defended, would also constitute substantial obstacles to an invader. The Aigaleos range, dividing the plain of Eleusis from the plain of Athens, was and is foremost in importance among these, and the strategic value of defending the Aigaleos-Parnes gap in particular must have been clearly recognized when Xenophon wrote this passage. It may well have been a defensive position for the Athenians at the time of the invasions of Kleomenes in 506 and of Pleistoanax in 446, both of which penetrated no farther than the plain of Eleusis.[27] The gap was the passage for Ar-


chidamos in 431, when the Spartans began a series of general invasions of Attica. The young Xenophon probably had personal experience observing the operations of the Peloponnesian army during the last years of the Dekeleian War, when he served as a cavalryman.[28] He would have been only one among many Athenians to notice the ways in which the terrain of Attica constrained, at certain points, the movements of the massed forces of the Peloponnesians.

Like Xenophon, Plato also recognized the value of a force trained for mountain fighting in the defense of a state with mountainous frontiers.[29] Writing in the Laws of a hypothetical state to be founded in the rugged terrain of Crete, Plato recommends not only that its citizens be trained as hoplites and cavalrymen, but also that they be drilled in skirmishing tactics with light arms and that they practice capturing positions and ambushing the enemy.[30] Young men are to be chosen by officers to spend two years of duty on patrol in the countryside, with the particular object of becoming thoroughly familiar with the terrain they may have to defend.[31] One of the tasks of these young men is to construct field-works of a type generally comparable to the Dema wall, "so that the countryside will be well barricaded against the enemy."[32]

The importance of topography for defensive planning is recognized by Plato in much the same way as it is by Xenophon and Aeneas. All three writers, in fact, advocate very much the same approach to territorial defense, and together they embrace all aspects of strategic and tactical planning evident in the defensive scheme of the Dema. They assume that defending forces will be composed of an appropriate balance of hoplites, light infantry, and cavalry, and Xenophon and Plato make special mention of the utility of light-armed infantry for fighting in broken terrain. This overall composition of forces, and the emphasis on light-armed infantry, is entirely appropriate to the defense of the Dema in particular and of the passes of the frontiers to the west in general. A two-tiered defensive scheme involving the positioning of flexible advanced units in the mountains of the frontiers and the establishment of a second, more unyielding, defensive line along Aigaleos and in the Aigaleos-Parnes gap accords well with the general advice of Aeneas and


the specific observations of Xenophon on Attic topography. The need mentioned by Aeneas for signal communication among these defensive units is satisfied by the system of signal posts related to the Dema tower. The use of fieldworks to reinforce the natural barriers of the country-side is specifically recommended by Plato. We may conclude that the strategy behind the construction of the Dema wall as outlined in this chapter is not only plausible but is typical of defensive theory and practice current in the second quarter of the fourth century.

The approach to territorial defense comprised in these doctrines of Aeneas, Xenophon, and Plato is a distinctive feature of fourth-century military theory and practice, distinctive especially for the Athenians by contrast to the policy and practices they had adopted under the guidance of Perikles during the Peloponnesian War.[33] As useful as the experience of Athens during the Peloponnesian War was as a rhetorical foil for fourth-century politicians, however, it is most unlikely that practical doctrines of territorial defense evolved in the fourth century simply as retrospective reactions against the failure of the Periklean strategy for the defense of Athens in the fifth century. The particular defensive strategies advocated in these writings of the 360s and 350s must have been developed in practice, where they had actually demonstrated their appropriateness to contemporary conditions. In fact, these circumstances may be recognized in the events of the Boiotian War.

From the outset of that war, light-armed troops attempted to hold mountain passes against invading armies; fieldworks for territorial defense were deployed around Thebes; mountaintop lookouts and signal posts were employed.[34] Although none of these elements was without precedent before the Boiotian War, all of them were integrated for the first time into a comprehensive strategy for the defense of Thebes (and, as argued here, Athens) against Peloponnesian forces in 378. By contrast, the strategies of these same states in the Corinthian War were much more traditional. That war opened with a series of pitched battles and soon lapsed into a prolonged war of attrition. At no time during the Corinthian War did all of the elements of territorial defense as described above come into play. But with the outbreak of the next war among the major powers of Greece, the Boiotian War, they are all employed, and examples of similar defensive preparations may be cited in the decades immediately following.[35] This is the period when the most distinctive


features of fourth-century defensive strategy were put into action, features that, by the middle of the century, could be considered standard practice.[36] The evidence, both historical and archaeological, indicates that the Dema wall was a product of the original formulation of this strategy in 378.

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