History of the Peloponnesian War

But the cause of their holding out was that the Lacedaemonians had called for volunteers to convey to the island ground corn and wine and cheese and other food such as might be serviceable in a siege, fixing a high price and also promising freedom to any Helot who should get food in. Many took the risk, especially the Helots, and actually brought it in, putting out from any and every point in the Peloponnesus and coming to shore during the night on the side of the island facing the sea.

If possible they waited for a wind to bear them to the shore;

for they found it easier to elude the guard of triremes when the breeze was from the sea, since then it was impossible for the ships to lie at their moorings off the island, whereas they themselves ran ashore regardless of consequences, as a value had been set upon the boats which they drove upon the beach, and the hoplites would be on watch for them at the landing-places on the island. All, on the other hand, who made the venture in calm weather were captured.

At the harbour, too, there were divers who swam to the island under water, towing after them by a cord skins filled with poppy-seed mixed with honey and bruised linseed; at first they were not discovered, but afterwards watches were set for them.

And so both sides kept resorting to every device, the one to get food in, the other to catch them doing it.