The search for even greater power at sea resulted in the creation of the trireme, a galley with three banks of oarsmen. These very expensive vessels carried as many as 170 oarsmen and dominated the Mediterranean from the 6th century to the 4th century BC. Athens invested heavily in triremes and had the finest navy afloat at the start of the Peloponnesian War (431-404 BC), a struggle for power between Athens and Sparta.
Athens's naval dominance proved temporary, however. In 404 BC incompetent Athenian admirals lost the fleet and the war. The problem with oared vessels was they could not carry sufficient food or water to sustain their crews long at sea. So the admirals ordered the galleys beached and sent the crew ashore for food and water. While the crew was away, Spartans attacked and destroyed the once mighty Athenian fleet.