Histories

On the third day, however, the barbarian admirals, finding it hard to bear that so few ships should do them hurt and fearing Xerxes' anger, waited no longer for the Greeks to begin the fight, but gave the word and put out to sea about midday. So it came to pass that these sea-battles were fought on the same days as the land-battles at +Thermopylae [22.5583,38.8] (Perseus) Thermopylae;

the seamen's whole endeavor was to hold the Euripus while Leonidas' men strove to guard the passage; the Greeks were ordered to give the barbarian no entry into Greece [22,39] (nation), EuropeHellas, and the Persians to destroy the Greek host and win the strait.