History of the Peloponnesian War

The Corinthians not consenting to this, a delay ensued, during which the Athenians conceived suspicions of what was preparing at Chios, and sent Aristocrates, one of their generals, and charged them with the fact, and upon the denial of the Chians, ordered them to send with them a contingent of ships, as faithful confederates. Seven were sent accordingly.

The reason of the despatch of the ships lay in the fact that the mass of the Chians were not privy to the negotiations, while the few who were in the secret did not wish to break with the multitude until they had something positive to lean upon, and no longer expected the Peloponnesians to arrive by reason of their delay.