Byzantine Empire - C. W. C. Oman |
By dethroning Theodosius III. on the very eve of the great Saracen invasion, Leo the Isaurian took upon himself the gravest of responsibilities. With a demoralized army, which of late had been more accustomed to revolt than to fight, a depleted treasury, and a disorganized civil service, he had to face an attack even more dangerous than that which Constantine IV. had beaten off thirty years before. Constantine too, the fourth of a race of hereditary rulers, had a secure throne and a loyal army, while Leo was a mere adventurer who had seized the crown only a few months before he was put to the test of the sword.
The reigning Caliph was now Suleiman, the seventh of the house of the Ommeyades. He had strained, all the resources of his wide empire to provide a fleet and army adequate to the great- enterprise which he had taken in hand. The chief command of the expedition was given to his brother Moslemah, who led an army of eighty thousand men from Tarsus across the centre of Asia Minor, and marched on the Hellespont, taking the strong city of Pergamus on his way. Meanwhile a fleet of eighteen hundred sail under the vizier Suleiman, namesake of his master the Caliph, sailed from Syria for the Aegean, carrying a force no less than that which marched by land. Fleet and army met at Abydos on the Hellespont without mishap, for Leo had drawn back all his resources, naval and military, to guard his capital.
In August, 717, only five months after his coronation, the Isaurian saw the vessels of the Saracens sailing up the Propontis, while their army had crossed into Thrace and was approaching the city from the western side. Moslemah caused his troops to build a line of circumvallation from the sea to the Golden Horn, cutting Constantinople off from all communication with Thrace, while Suleiman blocked the southern exit of the Bosphorus, and tried to close it on the northern, side also, so as to prevent any supplies coming by water from the Euxine. Leo, however, sallied forth from the Golden Horn with his galleys and fire-vessels bearing the dreaded Greek fire, and did "so much harm to the detachment of Saracen ships which had gone northward up the strait, that the blockade was never properly established on that side.
The Saracens relied more on starving out the city than on taking it by storm: they had come provided with everything necessary for a blockade of many months, and sat down as if intending to remain before the walls for an indefinite time. But Constantinople had been provisioned on an even more lavish scale; each family had been bidden to lay in a stock of corn for no less a period than two years, and famine appeared in the camp of the besiegers long ere it was felt in the houses of the besieged. Nor had Moslemah and Suleiman reckoned with the climate. Hard winters occasionally occur by the Black Sea, as the troops learnt to their cost in the Crimean War. But the Saracens were served even worse by the winter of 717-718, when the frost never ceased for twelve weeks. Leo might have boasted, like Czar Nicholas, that December, January, and February were his best generals for these months wrought fearful havoc in the Saracen host. The lightly clad Orientals could not stand the weather, and died off like flies of dysentery and cold. The vizier Suleiman was among those who perished. Meanwhile the Byzantines suffered little, being covered by roofs all the winter.
When next spring came round Moslemah would have had to raise the siege if he had not been heavily reinforced both by sea and land. A fleet of reserve arrived from Egypt, and a large army came up from Tarsus and occupied the Asiatic shores of the Bosphorus.
But Leo did not despair, and took the offensive in the summer. His fire-ships stole out and burnt the Egyptian squadron as it lay at anchor. A body of troops landing on the Bithynian coast, surprised and cut to pieces the Saracen army which watched the other side of the strait. Soon, too, famine began to assail the enemy; their stores of provisions were now giving out, and they had harried the neighbourhood so fiercely that no more food could be got from near at hand, while if they sent foraging parties too far from their lines they were cut off by the peasantry. At last Moslemah suffered a disaster which compelled him to abandon his task. The Bulgarians came down over the Balkans, and routed the covering army which observed Adrianople and protected the siege on the western side. No less than twenty thousand Saracens fell, by the testimony of the Arab historians themselves, and the survivors were so cowed that Moslemah gave the order to retire. The fleet ferried the land army back into Asia, and both forces started homeward. Moslemah got back to Tarsus with only thirty thousand men at his back, out of more than a hundred thousand who had started with him or come to him as reinforcements. The fleet fared even worse: it was caught by a tempest in the Aegean, and so fearfully shattered that it is said that only five vessels out of the whole Armada got back to Syria unharmed.
Thus ended the last great endeavour of the Saracen to destroy Constantinople. The task was never essayed again, though for three hundred and fifty years more wars were constantly breaking out between the Emperor and the Caliph. In the future they were always to be border struggles, not desperate attempts to strike at the heart of the empire, and conquer Europe for Islam. To Leo, far more than to his contemporary the Frank Charles Martel, is the delivery of Christendom from the Moslem danger to be attributed. Charles turned back a plundering horde sent out from an outlying province of the Caliphate. Leo repulsed the grand-army of the Saracens, raised from the whole of their eastern realms, and commanded by the brother of their monarch. Such a defeat was well calculated to impress on their fatalistic minds the idea that Constantinople was not destined by providence to fall into their hands. They were by this time far removed from the frantic fanaticism which had inspired their grandfathers, and the crushing disaster they had now sustained deterred them from any repetition of the attempt. Life and power had grown so pleasant to them that martyrdom was no longer an "end in itself"; they preferred, if checked, to live and fight another day.
Leo was, however, by no means entirely freed from the Saracens by his victory of 718. At several epochs in the latter part of his reign he was troubled by invasions of his border provinces. None of them, however, were really dangerous, and after a victory won over the main army of the raiders in 739 at Acroinon in Phrygia, Asia Minor was finally freed from their presence.