Tetramnestos (ruled c. 480 – 479 BCE) was, according to Herodotus, a King of Sidon who assisted the Achaemenid Emperor Xerxes I in the Second Persian invasion of Greece in 480 BCE.[1][2] Specifically, he is said to have served as the chief advisor of Xerxes in naval matters.[1] In effect, the Sidon fleet held a position of primacy among the naval forces of the Achaemenid Empire at that time, providing the best ships in the fleet, superior even to the fleet of Artemisia of Halicarnassus.[1] The Phoenicians furnished a fleet of 300 ships, "together with the Syrians of Palestine".[1]