Leo followed up this spectacular naval victory by transporting a force from the garrison of the city to the opposite shore of the Bosphorus, attacking the army encamped there and driving it in rout. Meanwhile the Bulgarian chieftain had responded to Leo's appeal and, relieving the siege of Adrianople, beat back the Saracen army at that point with great slaughter. The fugitives of that army served to throw into panic the troops encamped round the walls of Constantinople, already demoralized by disease, the death of their leaders, and the annihilation of the African and Egyptian fleets in the Bosphorus. The great retreat began. The Arab soldiers started back through Asia Minor, but only 30,000 out of the original force of 180,000 lived to reach Tarsus. The fleet set sail for the AEgean, and as in the similar retreat of a half century before, the Arabs were overwhelmed by a storm with terrible losses. The Christian ships picked off many survivors, and the Christians of the islands destroyed others that sought shelter in any port. It is said that out of the original armada of 1800 vessels only five returned to Syria! Thus the third and supreme effort of the Saracen ended in one of the greatest military disasters in history. The service of the Christian fleet in the salvation of the empire at this time is thus summarized by a historian: "The fleet won most of the credit for the fine defense; it invariably fought with admirable readiness and discipline, and was handled in the most masterful manner. It checked the establishment of a naval blockade at the very outset, and broke it when it was temporarily formed in 718; it enabled the army to operate at will on either shore of the Bosphorus, and it followed up the retreating Saracens and completed the ruin of the great armament."[1] [Footnote 1: THE BYZANTINE EMPIRE, Foard, p. 170.] The winning stroke in this campaign was the tremendous naval victory at the mouth of the Bosphorus, and this, even more emphatically than Constantine's victory in 677, deserves to be called another Salamis. Not only did it save the Christian empire but it checked the Caliphate at the summit of its power and started it on its decline. Not for thirty years afterwards was the Saracen able to put any considerable fleet upon the sea. It was ten years after the Arab defeat at Constantinople that the armies of the west began the other part of Muza's project--the conquest of the Franks. By this time the Frankish power was united and able to present a powerful defense. In six bitterly contested battles between Tours and Poitiers in 732 Charles Martel defeated the Arabs in a campaign that may well be called the Marathon, or better, the Plataea, of the Middle Ages, for it completed the work done by the imperial navy at Constantinople. From this time forward the power of the Saracen began to ebb by land and sea.