For the last five years of Constantinus’ long absence in the West there had been grievous trouble with the Saracens in Asia Minor, against which the caliph Muavia had launched his hosts for five successive summers. The raids of his generals reached as far as Amorium in Phrygia, which was stormed by the Arabs, and promptly retaken by the Romans in 668. The nominal control of affairs in Asia had been left to the emperor’s eldest son Constantine, when his father sailed to the West. [Sidenote: Constantine Pogonatus, 668-85.] On the news of the murder at Syracuse and the usurpation of Mezecius, Constantine, now aged eighteen, sailed in person to Sicily, put down and executed the usurper, and then promptly returned to Constantinople. He had been beardless when he set out, but returned next year with his face covered with hair, wherefore the people of the capital gave him the nickname of ‘Pogonatus,’ the bearded, by which he is generally known. Curiously enough the name would have been far better applied to his father whose beard was enormous, while that of Constantine V. did not exceed a very moderate limit. Constantine Pogonatus was his father’s true son, a hard-working, hard-fighting, and somewhat high-handed Caesar, who kept the empire well together, and spent all his energy in holding the Saracens in check, a task in which he won great success. He reigned for seventeen years (668-85), of which the first ten were a time of unbroken war with the Caliphate. The first beginning of this struggle was not very favourable for the empire; in 669-70 the generals of Muavia pushed their way as far as the sea of Marmora, and in 672 the Caliph thought success so nearly in his grasp that he prepared for a formal siege of Constantinople, the second that it had undergone in the century. Using the harbour of Cyzicus as their base, the Saracens, under a general named Abderrha-man, and the Caliph’s son Yezid, beleaguered the city for six months (April-September, 673). They were finally forced to retire after a naval engagement in which the Imperial galleys had the better, largely owing, it is said, to the newly invented ‘Greek fire,’ by which they burnt many of the Moslem ships. [Sidenote: Constantine V. saves Constantinople.] When forced away from the Bosphorus, the Saracens fell back on Cyzicus, which they succeeded in holding for no less than four years, making occasional sallies from it towards Constantinople, of which every single one was repelled with loss by the emperor. At last the Arabs, after losing their general, and seeing Abu Eyub, one of the last surviving companions of Mohammed, perish before the walls, raised the siege. Their fleet was destroyed by a storm off the Lycian Coast: their land-army was attacked on its retreat by the East-Romans, and defeated with a loss of 30,000 men.