History of the Peloponnesian War

The cause hereof were the Lacedaemonians, who had proclaimed that any man that would should carry in meal, wine, cheese, and all other esculents necessary for a siege into the island, appointing for the same a great reward of silver; and if any Helot should carry in any thing, they promised him liberty. Hereupon divers with much danger imported victual, but especially the Helotes, who, putting off from all parts of Peloponnesus, wheresoever they chanced to be, came in at the parts of the island that lay to the wide sea.

But they had a care above all to take such a time as to be brought in with the wind.

For when it blew from the sea, they could escape the watch of the galleys easily; for they could not then lie round about the island at anchor. And the Helotes were nothing tender in putting ashore, for they ran their galleys on ground, valued at a price in money; and the men of arms also watched at all the landing places of the island. But as many as made attempt when the weather was calm were intercepted.

There were also such as could dive, that swam over into the island through the haven, drawing after them in a string bottles filled with poppy tempered with honey, and pounded linseed; whereof some at the first passed unseen, but were afterwards watched.

So that on either part they used all possible art, one side to send over food, the other to apprehend those that carried it.