Emboldened by the easy successes of his armies over those of the ephemeral sovereigns who followed Justinian II., the caliph Soliman at last resolved to fit out an expedition on the largest scale against Constantinople. [Sidenote: Saracen invasion, 716.] A hundred thousand men advanced by land from Tarsus, while a fleet of more than 1000 sail gathered in the ports of Syria, and sailed round Asia Minor into the Ægean. The Caliph’s brother Moslemah was to head the whole expedition. Cappadocia was already in Saracen hands, and the Caliph’s vanguard was occupied with the siege of Amorium, the chief stronghold of Phrygia. That town, indeed, was saved from destruction by Leo the Isaurian, the governor of the Anatolic theme. But soon after, while the Arabs were still advancing, this same Leo, after concluding a private truce with the invaders, proclaimed himself emperor, and advanced against Constantinople, instead of reserving his strength to resist the armies of Soliman (716). [Sidenote: Leo the Isaurian, 717.] Once more fortune favoured the newest rising against the emperor of the day. The troops of Leo beat those of Theodosius III., and then the latter voluntarily abdicated and sent to offer his crown to the victor. He was a mild and virtuous man, who had been raised to the purple against his will by his military partisans, and longed to return to his obscurity, feeling himself destitute of the power needed to cope with the insurgents, and still more unable to face the impending Saracen invasion. Accordingly the senate and the patriarch formally elected the rebel Leo as emperor, and set him on the throne which had already changed masters seven times in the last twenty-two years. At length the empire had found a master who could defend what he had won, and was fully able to transmit his power to his heirs. The armament of Moslemah might be awaited without dismay, for the state was once more in the hands of one who could be trusted to use its resources aright. Leo was to dissipate once and for all the Saracen storm-cloud, and to free Constantinople from all danger from the East for more than three hundred years. But his achievements demand a chapter to themselves. ------------------------------------------------------------------------ CHAPTER XV THE HISTORY OF THE GREAT MAYORS OF THE PALACE 656-720 The Mayor Grimoald unsuccessfully endeavours to make his son king of Austrasia—Decadence of the house of the Merovings—Ebroin and his tyrannical rule in Neustria—Long civil wars—Rise of Pippin the younger and his victory at Testry—The ascendency of Pippin: his successes in consolidating the kingdom—Missionary enterprises in Germany—Civil wars at the death of Pippin—Final triumph of his son Charles Martel.