Constans II., when once he had made peace with Moawiah, would have done well to turn to the Balkan Peninsula, and evict the Slavs from the districts south of Haemus into which they had penetrated during the reign of Heraclius. But he chose instead to do no more than compel the Slavs to pay homage to him and give tribute, and set out to turn westward, and endeavour to drive the Lombards out of Italy. Falling on the Duchy of Benevento, he took many towns, and even laid siege to the capital. But he failed to take it, and passed on to Rome, which had not seen the face of an emperor for two hundred years. When an emperor did appear he brought no luck, for Constans signalized his visit by taking down the bronze tiles of the Pantheon and sending them off to Constantinople [664]. The Emperor lingered no less than five years in the West, busied with the affairs of Italy and Africa, till the Constantinopolitans began to fear that he would make Rome or Syracuse his capital. But in 668 he was assassinated in a most strange manner. “As he bathed in the baths called Daphne, Andreas his bathing attendant smote him on the head with his soap-box, and fled away.” The blow was fatal, Constans died, and Constantine his son reigned in his stead. Constantine IV., known as Pogonatus, “the Bearded,” reigned for seventeen years, of which more than half were spent in one long struggle with the Saracens. Moawiah, the first of the Ommeyades, had now made himself sole Caliph; the civil wars of the Arabs were now over, and once more they fell on the empire. Constantine’s reign opened disastrously, with simultaneous attacks by the armies and fleets of Moawiah on Africa, Sicily, and Asia Minor. But this was only the prelude; in 673 the Caliph made ready an expedition, the like of which had never yet been undertaken by the Saracens. A great fleet and land army started from Syria to undertake the siege of Constantinople itself, an enterprise which the Moslems had not yet attempted. It was headed by the general Abderrahman, and accompanied by Yezid, the Caliph’s son and heir. The fleet beat the imperial navy off the sea, forced the passage of the Dardanelles, and took Cyzicus. Using that city as its base, it proceeded to blockade the Bosphorus. The great glory of Constantine IV. is that he withstood, defeated, and drove away the mighty armament of Moawiah. For four years the investment of Constantinople lingered on, and the stubborn resistance of the garrison seemed unable to do more than stave off the evil day. But the happy invention of fire-tubes for squirting inflammable liquids (probably the famous “Greek-fire” of which we first hear at this time), gave the Emperor’s fleet the superiority in a decisive naval battle. At the same time a great victory was won on land and thirty thousand Arabs slain. Abderrahman had fallen during the siege, and his successors had to lead back the mere wrecks of a fleet and army to the disheartened Caliph.