History of the Peloponnesian War

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.

And they sank eleven of the Syracusan ships, slaying most of the men, except only the crews of three ships, whom they took alive; but of their own ships three were destroyed. And drawing up on shore the wrecks of the Syracusan ships and setting up a trophy on the little island that faces Plemmyrium, they withdrew to their own camp.