Achaemenid navy

thumb|Fleet of triremes made up of photographs of the modern full-sized replica Olympias (trireme)|Olympias A trireme ( ; ; cf. ) was an ancient vessel and a type of galley that was used by the ancient maritime civilizations of the Mediterranean Sea, especially the Phoenicians, ancient Greeks and Romans.

thumb thumb|Coinage of Tennes, king of [[Sidon, dated 351/0 BC. Phoenician pentekonter sailing left. Date above (here faint), waves below. King of Persia standing right, holding up lion by lock of mane; Aramaic T’ between.]] The penteconter (alt. spelling pentekonter, pentaconter, pentecontor or pentekontor; , pentēkónteros, "fifty-oared"), plural penteconters, was an ancient Greek galley in use since the archaic period.

military unit