five or six rows of oarsmen were commonplace and carried large complements of soldiers and catapults. With high freeboard (up to 3 m) and additional tower structures from which missiles could be shot down onto enemy decks, they were intended to be like floating fortresses. Designs with everything from eight rows of oarsmen and upward were built, but most of them are believed to have been impractical show pieces never used in actual warfare. Ptolemy IV, the Greek pharaoh of Egypt 221–205 BC, is recorded as building a gigantic ship with forty rows of oarsmen, though no specification of its design remains. One suggested design was that of a huge trireme catamaran with up to 14 men per oar and it is assumed that it was intended as a showpiece rather than a practical warship. With the consolidation of Roman imperial power, the size of both fleets and galleys decreased considerably. The huge polyremes disappeared and the fleet were equipped primarily with triremes and liburnians, compact biremes with 25 pairs of oars that were well suited for patrol duty and chasing down raiders and pirates. In the northern provinces oared patrol boats were employed to keep local tribes in check along the shores of rivers like the Rhine and the Danube. As the need for large warships disappeared, the design of the trireme, the pinnacle of ancient war ship design, fell into obscurity and was eventually forgotten. The last known reference to triremes in battle is dated to 324 at the Battle of the Hellespont. In the late 5th century the Byzantine historian Zosimus declared the knowledge of how to build them to have been long since forgotten. Middle Ages The earliest medieval galley specification comes from an order of Charles I of Sicily, in 1275 AD. Overall length 39.30 m, keel length 28.03 m, depth 2.08 m. Hull width 3.67 m. Width between outriggers 4.45 m. 108 oars, most 6.81 m long, some 7.86 m, 2 steering oars 6.03 m long. Foremast and middle mast respectively heights 16.08 m, 11.00 m; circumference both 0.79 m, yard lengths 26.72 m, 17.29 m. Overall deadweight tonnage approximately 80 metric tons. This type of vessel had two, later three, men on a bench, each working his own oar. This vessel had much longer oars than the Athenian trireme which were 4.41 m & 4.66 m long. This type of warship was called