History of the Peloponnesian War

When the fleet was ready, Gylippus led out his whole land-force under cover of night, intending in person to make an assault by land upon the forts of Plemmyrium, and at the same time, on a preconcerted signal, thirty-five Syracusan triremes sailed to the attack from the Great Harbour, while forty-five sailed round from the lesser harbour, where their ship-yard was, purposing to form a junction with those inside the harbour and simultaneously attack Plemmyrium, so that the Athenians, thus assailed from both directions, might be thrown into confusion.

But the Athenians, hastily manning sixty ships to oppose them, with twenty-five engaged the thirty-five Syracusan ships that were in the Great Harbour, and with the rest went to meet the squadron that was sailing round from the ship-yard. And so they at once engaged in battle in front of the mouth of the Great Harbour, and for a long time held out against one another, one side wishing to force the entrance, the other to prevent this.

Meanwhile Gylippus, noticing that the Athenians on Plemmyrium had gone down to the sea and were giving their attention to the sea-fight, surprised them by making a sudden attack at daybreak upon the forts; and first he captured the largest, and afterwards the two smaller ones also, their garrisons not awaiting the attack when they saw the largest so easily taken.

Of the garrison of the fort that was taken first, all that succeeded in escaping to the boats and to a certain merchant ship were rescued and brought to camp, but it was with difficulty; for the Syracusans were at the time having the best of the fight with their ships in the Great Harbour, and a trireme, and that a fast sailer, was sent in pursuit. But when the other two forts were taken, the Syracusans, as it chanced, were by this time losing the fight, and those who fled from these forts had less difficulty in sailing past them.

For the Syracusan ships that were fighting in front of the entrance, after they had forced back the Athenian ships, sailed into the harbour in disorder, and falling foul of one another made a present of their victory to the Athenians, who routed not only this squadron but also the ships by which they were at first being beaten inside the harbour.