History of the Peloponnesian War

On their arrival, the truce concluded at Pylus was immediately at an end, and the Lacedaemonians asked back their ships, according to agreement. But the Athenians, alleging as grounds of complaint an attack on the fort in contravention of the truce, and other particulars which appear not worth mentioning, refused to return them; laying stress on its having been said, that if there were any violation of it whatever, the truce was at an end. The Lacedaemonians denied it, and charging them with injustice in their conduct respecting the ships, went away, and set themselves to the war.

And now hostilities were carried on at Pylus with the greatest vigour on both sides; the Athenians cruising round the island continually with two ships in opposite directions during the day, while by night they were all moored round it, except on the side of the open sea, whenever there was a wind blowing; (twenty ships too had joined them from Athens to assist in the blockade, so that in all they amounted to seventy; and the Peloponnesians being encamped on the continent, and making attacks on the fort, on the look-out for an opportunity, should any offer, of rescuing their men.