It is unfortunate that there was no Herodotus to tell the details of this victory, for it was tremendously important to European civilization. Western Europe was then a welter of barbarism and anarchy, and if Constantinople had fallen, in all probability the last vestige of Roman civilization would have been destroyed. Moreover, the battle is of special interest from a tactical point of view because it was won by a new device, Greek fire, which was the most destructive naval weapon up to the time when gunpowder and artillery took its place. Indeed this substance may be said to have saved Christian civilization for several centuries, for the secret of its composition was carefully preserved at Constantinople and the Arabs never recovered from their fear of it. The victory did not, however, mark the crisis of the struggle. In the half century that followed, Constantinople suffered from weak or imbecile emperors while the Caliphate gained ground under able rulers and generals. In the first fifteen years of the eighth century the Saracens reached the climax of their power. Under a great general, Muza, they conquered Spain and spread into southern France. It was he who conceived the grandiose plan of conquering Christendom by a simultaneous attack from the west and from the east, converging at the city of Rome. One army was to advance from Asia Minor and take Constantinople; another was to cross the Pyrenees and overrun the territory of the Franks. Had the enterprise been started at the time proposed there could have been little opposition in the west, for the Franks were then busy fighting each other, but luckily Muza fell into disgrace with the Caliph at this time and his great project was undertaken by less able hands and on a piecemeal plan. The eastern line of invasion was undertaken first in the year 717. A fleet of warships and transports to the number of 1800 sailed to the Hellespont, carrying about 80,000 troops, while a great army collected at Tarsus and marched overland toward the same destination. Meanwhile two more fleets were being prepared in the ports of Africa and Egypt, and a third army was being collected to reenforce the first expedition. This army was to be under the personal command of the Caliph himself. The third attack on the Christian capital was intended to be the supreme effort. Fortunately, the ruler of Constantinople at this hour of peril was a man of ability and energy, Leo III; but the empire had sunk so low as a result of the misrule of his predecessors that his authority scarcely extended beyond the shores of the Sea of Marmora, and his resources were at a low ebb. The navy on which so much depended was brought to a high point of efficiency, but it was so inferior in numbers to the Saracen armada that he dared not attempt even a defense of the Dardanelles.