When Agesilaos departed from Boiotia in 377, he must have held some hope that the next season could yet see the Spartans in a stronger position in Boiotia. That could only be achieved by even greater commitments of manpower year-round to the war on this front. The process of escalation had already begun in 378 with the dispatch of a Spartan mora to Thespiai, and now it had been furthered by the installation of Panthoidas and a Peloponnesian force ("numerous," according to Plutarch Pelopidas 15.4, but of unknown size) at Tanagra. In his visit to the authorities in Megara after he had disbanded the allies, Agesilaos was probably concerned above all with securing more vigorous Megarian support in patrolling and guarding Kithairon.[59] For Agesilaos knew that the forces he had left in Boiotia would now have their hands full with other tasks.
If another Peloponnesian invasion the following year was to have any better chance of success than Agesilaos had had, the Spartans would have to establish their dominance in the Asopos valley before the next
spring. Counting Peloponnesian league contingents, Boiotian allies, and mercenaries, the Spartans must now have had far more than ten thou-sand men at their disposal in Boiotia, although the largest parts of these forces were divided between Thespiai and Tanagra. By combined actions, they might perhaps achieve against the Thebans alone what Agesilaos and the full Peloponnesian levy could not achieve against the The-bans and Athenians together. Failing any decisive battle, Agesilaos could hope that, with a major force now based at Tanagra, the Spartans would be in a better position to intercept Chabrias the following summer. In the meantime, these men would more vigorously carry on the war through plundering raids, in part to contribute to their own maintenance, while defending their allies' lands. In this process, they would gain familiarity with the terrain and perhaps establish their own system of lookouts and intimidate or even eliminate some of the Athenian advanced watchposts.
The Thebans and Athenians were fully cognizant of these developments, and to judge by the results they achieved, we may assume that they responded in kind by concentrating their own forces and by taking the initiative away from the Spartans. The rout of the Spartans at Tanagra, resulting in the death of Panthoidas, sometime between the summers of 377 and 375 (Plutarch Pelopidas 15.4), was a product of their energetic response to the Spartan buildup. Plutarch attributes this success to the Thebans, as he does in every encounter of this war mentioned in his life of Pelopidas. Like the defeat of Phoibidas at Thespiai in 378, this rout might have been the outcome of a Theban expedition against Tanagra, but we cannot rule out the possibility that the Athenians had some part in it. The Athenians must certainly have viewed the gathering of forces at Tanagra as worrisome, and if they did not actually join the Thebans in neutralizing this threat, they at least responded by making sure that their garrisons and watchposts in the countryside, the
(Xenophon Hellenika 6.2.1), were prepared to react to any movement the Spartans might make against them.
In practical terms, this would have consisted of the appropriate placement of the watchposts and the sufficient strength of the garrisons. The Athenian garrison most directly concerned with any threat emanating from Tanagra and affecting Theban-Athenian communications was Panakton. If the fortress at Phyle was already built—and these circumstances provide the earliest, and possibly the most plausible, occasion for the construction of this fort—then its garrison would also have been affected. Further west, the deme and fortress at Oinoe, beside the route from Kithairon to Eleusis, must have been a central point of assembly and supply for forces guarding the northwestern frontier, while the most remote Athenian garrison post lay in the pass at Eleutherai. In this
quarter, too, there was no less need for vigilance now than there had been in the spring of 378.[60]
These garrisons dose to the frontiers did not have to match the man-power at the disposal of the Spartans just across the frontier, since signal relays to Eleusis and to Athens could summon relief in an emergency. But they did have to be strong enough both to maintain more or less continuous patrols and to assure that any surprise assault by the Spartan forces would have a negligible chance of success. The Athenians might not have felt at ease, however, with merely adequate garrisons under such circumstances. They probably felt the need to have strong forces ready on the frontiers for both defensive purposes, to respond immediately to any raid into the countryside or attack on a position, and for offensive purposes, to carry the war in the "off season" against the neigh-boring allies of Sparta and their Spartan garrisons. As long as the Athenians had the means, there was every incentive to make sure that war took a higher toll on the property and persons of the enemy than on Attica and Athenians. The total manpower requirements for the defense of the countryside, although impossible to calculate with any precision, must therefore have amounted to a considerable burden. A number on the order of 2,500 men would have been an absolute minimum figure for the year-round garrisoning of all of these posts and Eleusis as well.[61]
If, as I suggest, the Athenians were not satisfied with absolute minimums, the garrison force could have been double or even triple that number.