One of the most obvious policies for the western enemies of Mohammad was to enter into communication with his enemies in the orient and attempt to concert some common action. Such negotiations had been set on foot by Popes Nicholas and Calixtus. The last two sovereigns of the dynasty of the Grand Comneni of Trebizond, who were now the representatives of the Roman Empire, John IV and David, had endeavoured to organise an alliance of the principalities of Asia Minor and Armenia, and to gain the support of Persia. It was upon Uzun Hasan, prince of the Turcomans of the White Sheep, that they above all relied. In 1459 David wrote to the Duke of Burgundy announcing the conclusion of such a league, and expressing the conviction that, if east and west were to strike together now, the Ottoman could be abolished from the earth. But the league availed not David, when two years later Mohammad came to destroy the empire of Trebizond (1461), and Uzun Hasan left him in the lurch. He surrendered on the offer of favourable treatment; but he was not more fortunate than the King of Bosnia; he and his family were afterwards put to death. At the same time Mohammad seized Genoese Amastris, and likewise Sinope, an independent Seljuk state; and thus he became master of the whole southern board of the Pontic sea.
It was about this time (1460) that Pope Pius indited a most curious letter to Mohammad, proposing that the Sultan should embrace Christianity, and become, under the patronage of the Roman see, “Emperor of the Greeks and the East.” A little thing, he wrote, only a drop of water, will make you the greatest of mortals; be baptised, and without money, arms, or fleet, you will win the greatest lordship in Christendom. Had this chimerical proposal been seriously meant, it would argue in Aeneas an almost incredibly fanciful and unpractical mind; but, when we find that he himself composed Mohammad’s answer, we may infer that the letter was written as a rhetorical exercise, and never intended to be sent.
The prospect looked brighter in 1463, when the breach at length came between Venice and the Sultan. An offensive and defensive alliance was concluded between the Pope, Venice, and the King of Hungary; the Duke of Burgundy joined it. The co-operation of Venice seemed a security that business was meant at last. The Pope, though he was advanced in years, resolved to lead the Crusade himself; Ancona was appointed as the mustering-place; and thither streamed from all countries bands of poor and ill-furnished people, drawn by the hope of booty (1464). But neither the Venetian vessels which were to transport them to Greece, nor the princes who were to lead them, appeared; and Ancona and the whole country round about groaned under their excesses. When Pius arrived in June, he found but the remnant of a disbanded rabble; and, overcome with disappointment, this victim of an idea out of season fell ill and died.
Venice, unlike the Pope, was in contact with realities. The war had broken out in Greece by the Turkish capture of Argos, which a Greek priest betrayed. The Venetians laid siege to Corinth, and built a wall—the old “Six-mile” wall—across the Isthmus; and had they been directed by a brave and competent commander, they would have captured the key of the Morea. But, disheartened by defeat in some small engagements with Omar Pasha who had marched up from the south of the peninsula to raise the siege, they abandoned the defence of the Isthmus, before Mahmud Pasha, the grand vezir, arrived with an army from the north (1463). Their failure at this favourable tide put a term to their chances of recovering ground in the Peloponnesus. An ineffectual maritime war was prosecuted for the next six years (1464-9); and then the great blow to Venetian power was struck. At the beginning of June 1470 a fleet of 108 large galleys and nearly 200 small sail, commanded by Mahmud, set sail for the Euripus, and by land Mohammad himself led an army probably numbering about 80,000. The usual size of his armies seems to have been from 80,000 to 100,000, though they are generally set at far larger figures by the vanity of his defeated foes. The Sultan had resolved to rob Venice of her most valuable station, the strong fort of Chalcis or Egripos (which the Latins further corrupted to Negroponte, with an allusion to the bridge which connected it with the mainland). Against this great double armament Venice had nothing ready to oppose but the strength of the well-provisioned city’s walls, the resolution of the inhabitants, and thirty-five galleys which were in the Aegean under Nicolò da Canale. This captain could not venture to guard the Straits against the far superior squadron; but, had he remained hard by, he might, it was thought, have effectually impeded Mohammad’s construction of a bridge of boats from the mainland to the shore of the island. But he sailed away to beat up reinforcements in Crete. The siege operations lasted for four weeks. In a final storm Mohammad, apparently aided by treachery, took the city in the teeth of a desperate defence (July 12). All the Italians who survived the conflict were executed; the Greeks were enslaved. At this crisis Canale covered himself with shame. He had returned to the Euripus; his small squadron was within sight of the city; the garrison was signalling to him; and he made no effort to save the place. If he had broken the boat-bridge, as Hunyady had done at Belgrade, he would probably have rescued Negroponte; it was his plainest duty to try, and Venice punished him for his fainéance. After the fall of its bulwark, the whole island passed into Turkish hands.
The event created in the West little less consternation than the fall of Constantinople itself. Pope Paul II and old Cardinal Bessarion were fluttered; and Sixtus IV (who succeeded in 1471), in conjunction with Ferdinand of Naples, accomplished something more considerable than the western powers had yet done. They sent a number of galleys to join Pietro Mocenigo, an able seaman whom Venice had chosen captain of her fleet. At Samos in 1472 Mocenigo commanded 85 vessels, of which 48 were furnished by Venice and her dependencies, 18 by the Pope, 17 by Ferdinand, and 2 by Rhodes: an armament notable as the greatest that the combination of Christian powers at this time achieved. The Venetian admiral who had taken on board a number of Albanian stradioti conducted a war of raids with skill, swooping down and plundering Passagio, a trading-town over against Chios; burning Smyrna; pillaging the quays of Satalia, then a mart of the oriental spice-trade; helping the royal house of Cyprus. One brilliant feat was wrought by a Sicilian, who venturing into the Dardanelles with six companions fired the Turkish arsenal of Gallipoli, and expiated his daring by a cruel death. Such warfare was highly agreeable to the mercenaries who were paid on the system of receiving a part of the booty; but it was hopelessly ineffectual, and Venice recognised that war must be waged by land. The scene was shifted to Albania, where Scanderbeg’s legacy had fallen to Venice. Here all turned on the possession of Scodra (Scutari), the key of Albania, which had the same kind of strategic significance as Negroponte or Acrocorinth. The Sultan was determined to secure it, and Sulayman, governor of Rumelia, laid siege to it in 1474. He was repelled by its brave defender Antonio Loredano; and the stress of need which the inhabitants endured was shown, the moment the siege was raised, by their general rush for the gates to quench their thirst in the waters of the Bojana. In 1477 the Turks renewed their designs in this quarter by besieging Kroja, and at the same time their light cavalry (akindje) harassed Venice in the north by overrunning Friuli. The garrison of Kroja, reduced to eating their dogs and receiving no aid from Venice, submitted in the ensuing year, and Mohammad advanced to the second siege of Scodra. The Venetian republic was hard pressed. In these days its yearly revenue did not touch 100,000 ducats; nor could the Venetians at this moment expect aid from other powers; Ferdinand of Naples was actually intriguing with the Turk, and Friuli was exposed to the inroads of the infidels from Bosnia; the plague was raging in the lagoons. Unable to relieve Scodra, Venice resolved to make peace and consented to hard conditions, resigning Scodra and Kroja, Negroponte, Lemnos and the Mainote district in Laconia. She agreed to pay a yearly sum of 10,000 ducats for free commerce in the Ottoman dominions, and recovered the right of keeping as before a Bailo (consul) at Constantinople (January, 1479).
This peace was agreeable neither to the Pope nor to Hungary. King Matthias Corvinus fancied that he was born and trained to be a champion against the infidel. But other occupations prevented this remarkable ruler from achieving much in this direction. His greatest feat was the capture of Szabacs, a fortress on the Save built