At this point it is worth pausing to consider what the fighting ship of this period was like. As we have seen in the preceding chapter the Roman navy sank into complete decay. At the end of the fourth century there was practically no imperial navy in existence. The conquest of the Vandals by Belisarius in the sixth century involved the creation of a fleet, but when that task was over the navy again disappeared until the appearance of the Arabs compelled the building of a new imperial fleet. The small provincial squadrons then used to patrol the coasts were by no means adequate to meet the crisis. The warships of this period were called "dromons," a term that persists even in the time of the Turkish invasion eight centuries later. The word means "fast sailers" or "racers." The dromon was not the low galley of the later Middle Ages but a two-banked ship, probably quite as large as the Roman quinquereme, carrying a complement of about 300 men. Amidships was built a heavy castle or redoubt of timbers, pierced with loopholes for archery. On the forecastle rose a kind of turret, possibly revolving, from which, after Greek fire was invented, the tubes or primitive cannon projected the substance on the decks of the enemy. The dromon had two masts, lateen rigged, and between thirty and forty oars to a side. There were two classes of dromons, graded according to size, and a third class of ship known as the "pamphylian," which was apparently of a cruiser type, less cumbered with superstructure. In addition there were small scout and dispatch boats of various shapes and sizes. Both Christian and Saracen fought with these kinds of warships. Apparently the Arabs simply copied the vessels they found already in use by their enemies, and added no new device of their own. [Illustration: EUROPE'S EASTERN FRONTIER] In 655 Muaviah started his great double invasion against Constantinople. He sent his fleet into the AEgean, while he himself with an army tried to force the passes of the Taurus mountains. Before the Arab fleet had gone far it met the Christian fleet, commanded by the Emperor himself, off the town of Phaselis on the southwestern coast of Asia Minor. A great battle followed. The Christian emperor, Constantine II, distinguished himself by personal courage throughout the action, but the day went sorely against the Christians. At last the flagship was captured and he himself survived only by leaping into a vessel that came to his rescue while his men fought to cover his escape. It was a terrible defeat, for 20,000 Christians had been killed and the remnants of their fleet were in full retreat. But the Saracens had bought their victory at such a price that they were themselves in no condition to profit by it, and the naval expedition went no further. Meanwhile Muaviah had not succeeded in forcing the Taurus with his army, so that the grand assault came to nothing after all.