Purpose of the Dema Tower
The Dema tower has generally been considered to be a command post for troops manning the Dema wall. Arguments in favor of this view are presented by Jones, Sackett, and Eliot:
The Dema represents one general defensive scheme adopted for the whole pass, based on fluid tactics of counter-attack along a very wide front; it could not operate properly without an effective supervision, exercised from some central vantage point. The tower is the one point behind the wall which commands the greatest length of its undulating course, and was therefore suited for the observation of any hostile advances, and the signalling of local counter-attacks; for a Dema headquarters it was the best (and only) site.[29]
This explanation is founded on the dual premises that the defense of the Dema required a central command post and that the Dema tower
was located in the best (and only) spot to serve such a purpose. Both of these premises are false, the second most obviously so, since it can be disproved by simple observation on the spot.
As was noted in the first section of this chapter, the position of the tower on the highest point of Pyrgarthi leaves more than 600 meters of the wall near the tower concealed behind a secondary summit of Pyrgarthi (figures 21-22). Even if the tower originally stood as much as 11 meters high, not much more of the wall could have been seen from it.[30] This is a serious objection to the command-post theory. If the purpose of the tower required it to have a view of the entire length of the wall, as it would if it were to observe and signal operations along the wall, then it could have been built on the very secondary summit, only 130 meters away, which blocks the view from its actual site. The fact that the Dema tower could have been but was not so situated is sufficient to refute the command-post explanation.
It is quite doubtful that defensive operations along the Dema wall could have been effectively controlled from a central vantage point, even if the Dema tower had provided such a vantage. Visual or audible signals were effective in conveying only a limited number of previously agreed-upon messages, and on the battlefield signals might prompt the commencement of certain prearranged maneuvers but were usually no more than trumpet calls for the advance or the retreat.[31] Polybios observes that the sort of simple signal systems employed in his day were useless in the face of unforeseen circumstances, and the point certainly applies to signals on the battlefield, where the opportunities for surprise and confusion would be the greatest.[32] It is no wonder, then, that no example of an army commanded by signals from a central vantage point can be cited as a parallel for the supposed purpose of the Dema tower. It is significant in this connection that even in the defense of a city-wall perimeter under attack, Aeneas Tacticus assumes that the commanding general will be on the battlements leading his troops wherever they are hardest pressed and not issuing commands by signal from some headquarters, even though he expects that such a commander will have a signal post from which a general alert signal can be seen over the whole city.[33]
In addition to regarding the Dema tower as the command post of the Dema defenses, previous investigators have believed that signal com-
munications between the Dema and Athens would have been desirable and that the Dema tower served as the signal point at the wall.[34] Everywhere within the Aigaleos-Parnes gap, the view of Athens is blocked by the northern end of Mount Aigaleos, so some intermediate relay station would have been necessary for signals to be passed between the Dema tower and Athens. On the northernmost summit of Aigaleos, there are remains of a tower that has long been associated with the Dema defenses, and this has been interpreted as the relay station for communications between the Dema and Athens (maps 2, 5; figure 35).[35] From the Aigaleos tower there is a clear view of Athens, but it is impossible to see the Dema tower or any part of the main sector of the Dema wall because the summit of the mountain is too broad to allow a view into the valley to the north. Nor could the two towers ever have been tall enough to be in view of each other over the intervening shoulder of Aigaleos.[36] Other positions on the Aigaleos ridge would have been suitable for such a relay station between the Dema tower and Athens, if such communications were desirable, but the actual Aigaleos tower is not appropriately located to serve this purpose. Furthermore, there is no evidence that any such relay station was built, either on Aigaleos or elsewhere.[37] There is there-fore no reason to believe that the Dema tower ever served to communicate between the Aigaleos-Parnes gap and Athens.
The Dema tower provided a sheltered vantage point for a few men in a prominent position within the Aigaleos-Parnes gap. Since it must have been an observation post of some sort, it should be possible to see even now the places that were to be observed from the tower. We have just noted why it is doubtful that the tower was intended to communicate by signal with Athens and why it could not have served as a command post for the Dema wall. Considering the view beyond the wall, it is also apparent that the tower could not have been very effective in observing the movements of an enemy force approaching the wall, since like the view
of the wall itself, the nearer approaches to the wall are not all visible from the tower (figures 21-22). Furthermore, because it is well within the confines of Attica, it is highly improbable that the tower was meant to be a position from which enemy troop movements could be first detected. The tower could have served, however, as a post where men waited to receive and acknowledge visual signals coming from other observation posts closer to the frontiers of Attica.
The far side of the Eleusinian plain and the mountains of the frontier beyond are clearly in view from the tower site (figures 21-22, see also map 5, p. 99). Within this view, the town of Eleusis can be seen to the southwest, and to the northwest, the low summit of Plakoto and, above it, the higher summit of Velatouri stand out, marking the sites of fourth-century towers (see figures 37-40).[38] From the Velatouri tower, Panakton, Oinoe, and Eleutherai can be seen, and from these positions other outposts closer to the western frontiers are visible, making up a network of observation and signal posts through which the arrival of an enemy force on the frontiers could have been signaled to the interior of Attica. Signals coming to Eleusis from Salamis, or to Velatouri and Plakoto from the Kithairon frontier, could have been relayed across Aigaleos to Athens by the Aigaleos tower or by its companion on the summit of Korydallos to the south of the Sacred Way.[39] But the Dema tower, which could also receive these signals from the west, is in a very different position from these and other mountaintop towers in Attica. It sits not on a peak with wide long-distance views on all sides but on a hilltop that is comparatively enclosed within the Aigaleos-Parnes gap. Except for the nearer ground within the pass itself, it commands no view not already better surveyed from the Aigaleos tower. This very exception, however, pro-vides the decisive clue to its purpose: the Dema tower served to link the lookout and signal system of the western frontiers directly to Athenian forces at the wall in the Aigaleos-Parnes gap.
The Dema tower must have been built because it was of particular importance that signals from the west should be received and answered from the area of the Dema wall. As discussed in the previous chapter, the wall was only useful when it was manned by a sizable army. Since the defensive scheme of the Dema wall envisioned occasions when an army would be in place at the wall, it would clearly have been desirable for that army to receive the same warning signals or intelligence that might be sent from the frontiers to Athens. And since the commander of that
army must have been empowered to initiate actions in response to those signals, it would have been important for signals to be sent back from the Dema to Eleusis and to the outposts on the frontiers. The Dema tower was eminently suited to such a purpose. Located on the highest summit within this pass, it would have been readily visible and accessible to forces assembled in the vicinity of the Dema wall, and its position could easily have been discerned from afar. It must therefore have served as the communications center of a major Athenian military camp at the Dema wall.[40] The Dema tower was thus integral to the defensive scheme of the Dema wall, and furthermore, it was integral to a scheme that called for the placement of lookout and signal towers elsewhere in Attica.
Other towers, noted briefly above, indicated in map 5 below and illustrated in figures 34-40, are appropriately situated for the purposes of the lookout and signal system envisioned here, and these, on the evidence of masonry and surface sherds, were in use within the fourth century. Like the Dema tower, they are round, with solid rubble-filled bases. These resemblances and their functional suitability provide sufficient evidence to consider it probable that these lookout towers were employed along with the Dema wall as part of an integrated scheme for the defense of Attica. The Dema wall and tower are the most specialized works in this defensive system, and the interpretation of the whole depends upon a demonstration of the specific historical function of these key works. Chapter 4 will therefore bring together all of the various forms of evidence and lines of reasoning that, on historical as well as archaeological grounds, converge on the Boiotian War of 378-375 as the time of the creation of the Dema wall.