Syracuse had enjoyed a period of almost unbroken peace for nearly fifty years. She had had difficulties with other Greek cities, and had been threatened at one time by the ambitious schemes of a native prince, but had never actually felt the privations of a siege, or, indeed, any of the inconveniences of warfare. This accounts for the want of discipline that we have observed in her citizen soldiers, and even for the profound discouragement which prevailed. The question of surrender began to be discussed, and informal negotiations were opened with the Athenian commanders through persons whose politics led them to regard the possibility of submission without abhorrence. The peace-party indeed was but small, while the democracy, which was opposed to surrender, was overpoweringly strong. Hence there was no serious division to interfere with the defence. Nevertheless, the hope of making successful resistance was rapidly growing weaker. The prospects of the besiegers, on the other hand, were daily brightening. Most of the Greek cities of South Italy abandoned their attitude of indifference or hostility, and furnished supplies in abundance. The Etrurian maritime cities actually sent, in the shape of three fifty-oared ships-of-war, the help which they had promised at an earlier time, while the native tribes gave in their adherence. But Nicias, no longer having the energetic Lamachus at his side, neither considered seriously the willingness of the Syracusans to treat nor pushed the siege with vigour.
At Sparta and Corinth the cause of the besieged city was given up as lost. It was reported that the investment was complete, and that surrender was now merely a question of time. Gylippus, the Spartan, who had been struggling in vain to overcome the indifference of his countrymen, was still (in June 414) waiting for the complete equipment of the Corinthian fleet—for it was to Corinth, rather than to Sparta, that he looked for help. He had, however, four ships ready, two of them Spartan, two Corinthian, and with these he resolved to start. It was too late, he feared, to help Syracuse, but the Greek cities in Italy, which would be the next to be attacked, might yet be saved. Crossing the sea without misadventure, the Athenian ships being otherwise engaged, he put into Tarentum. This city was a Spartan colony, and for this reason, and also because Gylippus had many personal friends in it, it welcomed him with enthusiasm. At Thurii he met with a very different reception. The pro-Athenian party in this city was now dominant, and Gylippus could make no impression on the government. After leaving Thurii, he encountered a violent storm which drove him far to the south. Narrowly escaping shipwreck, he made his way back to Tarentum. Here he had to beach and refit his ships. This loss of time might well have proved fatal to the enterprise. But Nicias, by his negligence and supineness, let slip the opportunity that fortune had put in his hands. It seems that both he and the government of Thurii, from whom he heard that Gylippus was approaching, failed to appreciate the gravity of the incident. An adventurer who had no more than four ships with him seemed little better than a pirate. It was not worth while to take precautions against any mischief that he might do. The more acute Alcibiades had seen what powerful help there would be in the mere name and presence of a Spartan general.
Gylippus now learnt that the danger threatening Syracuse had been exaggerated. The city was not completely invested, and might still be entered by way of Epipolæ and the ridge that connected it with the high lands of the interior. Of course it was open to him still, as it had always been, to run the blockade of the Athenian ships and to make his way into the city by sea. Probably this seemed too hazardous. A Spartan was naturally more at home on land, and it was by land that he resolved to make the attempt. He sailed through the Strait of Messené. Even here he found no Athenian ships on guard. A small squadron of four arrived, indeed, at Rhegium shortly afterwards, but he was then out of reach of pursuit. Shortly afterwards he sailed along the north coast of the island, his destination being Himera, the only city of importance on that side of Sicily. There he hoped to levy a force strong enough to give him a chance of making his way into Syracuse, even against the resistance of the besiegers. Nor was he disappointed. The announcement that he was a Spartan and came on behalf of his country obtained for him a hearty welcome. Himera consented to join him with a muster of her own citizens, and to furnish with arms and armour such of his sailors and marines as wanted them. If A summons was sent to Selinus to send her whole available force to a specified spot on the line of march. A small contingent came in from Gela, and a thousand men from some of the native tribes, among whom, owing to the death of a friendly chief, Athens had lately lost ground. The whole force amounted to about 3000. With this he marched across the island, and making his way along the ridge that led into Epipolæ, effected unopposed a junction with the Syracusan army.
The besieged had received notice of his coming from the captain of one of the ships belonging to the Corinthian squadron. It had been left behind to repair an accident when the rest of the squadron set sail, but contrived, escaping the Athenian blockade, to reach Syracuse in advance. It arrived just in time. The Syracusans were deliberating in public assembly on the question of surrender, and were inclined to consent to it. The news that Gylippus was on his way to relieve the city made a complete change in their feeling. They now determined to resist to the last. It was not long before Gylippus was seen to be approaching. The whole armed force of the city marched out to meet him.
It is useless to speculate on the causes which led Nicias to permit these operations to be conducted without any attempt at resistance. Nothing, indeed, can be suggested as probable, except the inertia produced by the disease from which we know him to have been suffering. He knew of the mission of Gylippus; he must have heard from the commander of the small squadron sent to the Strait of Messené that he was on his way, and he must have been able to conjecture, almost with certainty, the route that he would take. He was not taken by surprise, for Gylippus must have spent some time in collecting his troops. And yet he made no effort to stop his advance. No attack was made upon him during his march, although, as Himera was not less than a hundred miles from Syracuse, there must have been many opportunities. Nor was there any attempt to block the one road, narrow and difficult though it was, by which Syracuse could be approached. A stranger instance of negligence in an experienced soldier cannot be found in the whole history of warfare.
The Spartan general, who at once took over the supreme command of all the Syracusan forces, lost no time in making a demonstration of his strength. He approached the Athenian line with his army in order of battle. The besiegers, astonished though they were for a time by his unexpected appearance, did not refuse the challenge, but took up a position in front of the wall. Gylippus then sent a herald with the proposition that if the Athenians would evacuate Sicily within five days, they would be allowed to do so without molestation. To this Nicias did not condescend to make any reply. This proceeding took up some time, and gave the Spartan what he probably wished to have—an opportunity of estimating the quality of the troops under his command. This did not satisfy him, and he accordingly retired to some more open ground nearer the Syracusan lines. Here he could more easily manœuvre his inexperienced infantry and have the help of his cavalry. Nicias did not venture to follow him. This was really to acknowledge defeat. The garrison of the city had come outside the walls, and he declined to engage it; the capture of the city itself was plainly impossible. The inaction of the besiegers seems to have so improved the morale of the Syracusan troops that on the following day Gylippus made another demonstration in front of the line of investment. The besieging army made no movement in return. While it was thus occupied, the Spartan general attacked and captured the fort of Labdalum, putting all the garrison to the sword. The same day there happened another incident ominous of the end. One of the ships of the blockading squadron was captured.