(Σάλαιθυος), a Lacedaemonian, who, early in B. C. 427, when Mytilene had revolted from Athens, and had been received into the Spartan alliance, was sent thither to give promise of aid, and contrived to make his way into the city through the Athenian lines, where they were interrupted by the bed of a torrent. The expected succour, however, was so long in coming, that Salaethus himself at last despaired of it; and in order to increase the effective force of the besieged, he ventured to entrust the commons with the full armour of the regular infantry. The consequence was that they broke out into insurrection, and the oligarchical party, fearing lest they should capitulate apart for themselves, saw no resource but in the surrender of the city to the Athenians. Salaethus concealed himself, but was taken; and, together with the chief instigators of the revolt, was sent to Athens. Here he tried to save his life by making great offers, engaging in particular to prevail on the Lacedaemonians to abandon the siege of Plataea. The people, however, paid no regard to his promises, and sentenced him to immediate execution. (Thuc. 3.25, 27, 28, 35, 36.)