The bireme was an oared warship with two rows of oars on each side. It was a revolutionary invention (possibly by the Boeotian Greeks since the Trojan War or more probable their settlers, the Erythraeans in Asia Minor in the 8th century B.C.) which doubled the motion force of the ship without increasing its length. This was an important advantage in pirate persecutions and in the ramming of opponents (with the ram of the prow). Navigation was achieved with the two big oars of the stern. Complementarily, it had a large square sail with many pulleys for its unencumbered handling. It usually had 100 oars (“ekatontoros”). Its length and width reached 32 and 4.80 metres, respectively.
Sometimes it had a deck for the protection of the oarsmen and the facile transport of the warriors.