They were now impatient to set sail, but the Corinthians were not willing to accompany them until they had celebrated the Isthmian festival, which fell at that time. Upon this Agis proposed to them to save their scruples about breaking the Isthmian truce by taking the expedition upon himself. The Corinthians not consenting to this, a delay ensued, during which the Athenians conceived suspicions of what was preparing at Chios, and sent Aristocrates, one of their generals, and charged them with the fact, and, upon the denial of the Chians, ordered them to send with them a contingent of ships, as faithful confederates. Seven were sent accordingly. The reason of the dispatch of the ships lay in the fact that the mass of the Chians were not privy to the negotiations, while the few who were in the secret did not wish to break with the multitude until they had something positive to lean upon, and no longer expected the Peloponnesians to arrive by reason of their delay.
In the meantime the Isthmian games took place, and the Athenians, who had been also invited, went to attend them, and now seeing more clearly into the designs of the Chians, as soon as they returned to Athens took measures to prevent the fleet putting out from Cenchreae without their knowledge. After the festival the Peloponnesians set sail with twenty-one ships for Chios, under the command of Alcamenes. The Athenians first sailed against them with an equal number, drawing off towards the open sea. The enemy, however, turning back before he had followed them far, the Athenians returned also, not trusting the seven Chian ships which formed part of their number, and afterwards manned thirty-seven vessels in all and chased him on his passage alongshore into Spiraeum, a desert Corinthian port on the edge of the Epidaurian frontier. After losing one ship out at sea, the Peloponnesians got the rest together and brought them to anchor. The Athenians now attacked not only from the sea with their fleet, but also disembarked upon the coast; and a melee ensued of the most confused and violent kind, in which the Athenians disabled most of the enemy's vessels and killed Alcamenes their commander, losing also a few of their own men.
After this they separated, and the Athenians, detaching a sufficient number of ships to blockade those of the enemy, anchored with the rest at the islet adjacent, upon whkh they proceeded to encamp, and sent to Athens for reinforcements; the Peloponnesians having been joined on the day after the battle by the Corinthians, who came to help the ships, and by the other inhabitants in the vicinity not long afterwards. These saw the difficulty of keeping guard in a desert place, and in their perplexity at first thought of burning the ships, but finally resolved to haul them up on shore and sit down and guard them with their land forces until a convenient opportunity for escaping should present itself. Agis also, on being informed of the disaster, sent them a Spartan of the name of Thermon. The Lacedaemonians first received the news of the fleet having put out from the Isthmus, Alcamenes having been ordered by the ephors to send off a horseman when this took place, and immediately resolved to dispatch their own five vessels under Chalcideus, and Alcibiades with him. But while they were full of this resolution came the second news of the fleet having taken refuge in Spiraeum; and disheartened at their first step in the Ionian war proving a failure, they laid aside the idea of sending the ships from their own country, and even wished to recall some that had already sailed.
Perceiving this, Alcibiades again persuaded Endius and the other ephors to persevere in the expedition, saying that the voyage would be made before the Chians heard of the fleet's misfortune, and that as soon as he set foot in Ionia, he should, by assuring them of the weakness of the Athenians and the zeal of Lacedaemon, have no difficulty in persuading the cities to revolt, as they would readily believe his testimony. He also represented to Endius himself in private that it would be glorious for him to be the means of making Ionia revolt and the King become the ally of Lacedaemon, instead of that honour being left to Agis (Agis, it must be remembered, was the enemy of Alcibiades); and Endius and his colleagues thus persuaded, he put to sea with the five ships and the Lacedaemonian Chalcideus, and made all haste upon the voyage.
About this time the sixteen Peloponnesian ships from Sicily, which had served through the war with Gylippus, were caught on their return off Leucadia and roughly handled by the twenty-seven Athenian vessels under Hippocles, son of Menippus, on the lookout for the ships from Sicily. After losing one of their number, the rest escaped from the Athenians and sailed into Corinth.
Meanwhile Chalcideus and Alcibiades seized all they met with on their voyage, to prevent news of their coming, and let them go at Corycus, the first point which they touched at in the continent.
Here they were visited by some of their Chian correspondents and, being urged by them to sail up to the town without announcing their coming, arrived suddenly before Chios. The many were amazed and confounded, while the few had so arranged that the council should be sitting at the time; and after speeches from Chalcideus and Alcibiades stating that many more ships were sailing up, but saying nothing of the fleet being blockaded in Spiraeum, the Chians revolted from the Athenians, and the Erythraeans immediately afterwards. After this three vessels sailed over to Clazomenae, and made that city revolt also; and the Clazomenians immediately crossed over to the mainland and began to fortify Polichna, in order to retreat there, in case of necessity, from the island where they dwelt.