The Byzantine Empire in 1355.Encyclopædia Britannica, Inc.
Byzantium became a vassal state of the Turks, pledged to pay tribute and to provide military assistance to the Ottoman sultan. The possession of Constantinople thereafter was disputed by the Emperor’s sons and grandsons in a series of revolutions, which were encouraged and sometimes instigated by the Turks, the Genoese, or the Venetians. John V’s son Andronicus IV, aided by the Genoese and the sultan Murad I, mastered the city for three years (1376–79). He rewarded the Turks by giving back Gallipoli to them, and Murad made his first European capital at Adrianople. The Venetians helped John V to regain his throne in 1379, and the empire was once again divided into appanages under his sons. Only his second son, Manuel, showed any independence of action. For nearly five years, from 1382 to 1387, Manuel reigned as emperor at Thessalonica and laboured to make it a rallying point for resistance against the encroaching Turks. But the city fell to Murad’s army in April 1387. When the Turks then drove deeper into Macedonia, the Serbs again organized a counteroffensive but were overwhelmed at Kossovo in 1389. Manuel II and respite from the Turks
The loss of Thessalonica and the Battle of Kossovo sealed off Constantinople by land. The new sultan Bayezid I (1389–1402) intended to make it his capital; when Manuel II Palaeologus came to that throne at his father’s death in 1391, the Sultan warned him that he was emperor only inside the city walls. The Turks already controlled the rest of Byzantine Europe, except for the south of Greece.
Manuel II Paleologus, detail from a Greek manuscript, 15th century; in the Bibliothèque Nationale, Paris.Courtesy of the Bibliothèque Nationale, Paris
In 1393 Bayezid completed his conquest of Bulgaria, and soon afterward he laid siege to Constantinople. The blockade was to last for many years. Manuel II, like his father, pinned his hopes of rescue on the West. A great Crusade against the Turks was organized by the King of Hungary, but it was defeated at Nicopolis on the Danube in 1396. In 1399 the French marshal Boucicaut, who had been at Nicopolis and had returned to the relief of Constantinople with a small army, persuaded Manuel to travel to western Europe to put the Byzantine case in person. From the end of 1399 to June 1403 the Emperor visited in Italy, France, and England, leaving his nephew John VII in charge of Constantinople. Manuel’s journey did something to stimulate Western interest in Greek learning. His friend and ambassador in the West, Manuel Chrysoloras, a pupil of Demetrius Cydones, was appointed to teach Greek at Florence. The Pope instituted a defense fund for Constantinople. Interest and sympathy were forthcoming but little in the way of practical help. During Manuel’s absence, however, the Ottomans were defeated at Ankara by the Mongol leader Timur (Tamerlane) in July 1402. Bayezid was captured and his empire in Asia was shattered. His four sons contended with each other to secure possession of the European provinces, which had been little affected by the Mongol invasion, and to reunite the Ottoman dominions. In these wholly unexpected circumstances the Byzantines found themselves the favoured allies first of one Turkish contender, then of another. The blockade of Constantinople was lifted. Thessalonica—with Mount Athos and other places—was restored to Byzantine rule, and the payment of tribute to the sultan was annulled. In 1413 Mehmed I, helped and promoted by the emperor Manuel, triumphed over his rivals and became sultan of the reintegrated Ottoman Empire.
During his reign, from 1413 to 1421, the Byzantines enjoyed their last respite. Manuel II, aware that it could not last, made the most of it by strengthening the defenses and administration of the fragments of his empire. The most flourishing province in the last years was the Despotate of Morea. Its prosperity had been built up first by the sons of John Cantacuzenus (who died there in 1383) and then by the son and grandson of John V—Theodore I and Theodore II Palaeologus. Its capital city of Mistra became a haven for Byzantine scholars and artists and a centre of the last revival of Byzantine culture, packed with churches, monasteries, and palaces. Among its scholars was George Gemistus Plethon, a Platonist who dreamed of a rebirth of Hellenism on Hellenic soil. Final Turkish assault
When Murad II became sultan, in 1421, the days of Constantinople and of Hellenism were numbered. In 1422 Murad revoked all the privileges accorded to the Byzantines by his father and laid siege to Constantinople. His armies invaded Greece and blockaded Thessalonica. The city was then a possession of Manuel II’s son Andronicus, who in 1423 handed it over to the Venetians. For seven years Thessalonica was a Venetian colony, until, in March 1430, the Sultan assaulted and captured it. Meanwhile, Manuel II had died in 1425, leaving his son John VIII as emperor. John, who had already traveled to Venice and Hungary in search of help, was prepared to reopen negotiations for the union of the churches as a means of stirring the conscience of Western Christendom. His father had been skeptical about the benefits of such a policy, knowing that it would antagonize most of his own people and arouse the suspicion of the Turks. The proposal was made, however, at the Council of Florence in 1439, attended by the emperor John VIII, his patriarch, and many Orthodox bishops and dignitaries. After protracted and difficult discussions, they agreed to submit to the authority of Rome. The union of Florence was badly received by the citizens of Constantinople and by most of the Eastern Orthodox world. But it had its notable adherents, such as the bishops Bessarion of Nicaea and Isidore of Kiev, both of whom retired to Italy as cardinals of the Roman Church. Bessarion’s learning and library helped to encourage further Western interest in Greek scholarship. The union of Florence also helped to stimulate a Crusade against the Turks. Once again it was led by the king of Hungary, Władysław III of Poland, supported by George Branković of Serbia and by János Hunyadi of Transylvania. But there were disagreements among its leaders, and the Christian army was annihilated at Varna in 1444.
The Byzantine collapse and the Ottoman triumph followed swiftly thereafter. In 1448 Constantine XI (or XII), the last emperor, left Mistra for Constantinople when his brother John VIII died without issue. His two other brothers, Thomas and Demetrius, continued to govern the Morea, the last surviving Byzantine province. In 1449 Mehmed II (sultan 1444–46 and 1451–81) began to prepare for the final assault on Constantinople. No further substantial help came from the West, and the formal celebration of the union of the churches in Hagia Sophia in 1452 was greeted with a storm of protest. Even in their extremity, the Byzantines would not buy their freedom at the expense of their Eastern Orthodox faith. They found the prospect of being ruled by the Turks less odious than that of being indebted to the Latins. When the crisis came, however, the Venetians in Constantinople, and a Genoese contingent commanded by Giovanni Giustiniani, wholeheartedly cooperated in the defense of the city. Mehmed II laid siege to the walls in April 1453. His ships were obstructed by a chain that the Byzantines had thrown across the mouth of the Golden Horn. The ships were therefore dragged overland to the harbour from the seaward side, bypassing the defenses. The Sultan’s heavy artillery continually bombarded the land walls until, on May 29, some of his soldiers forced their way in. Giustiniani was mortally wounded. The emperor Constantine was last seen fighting on foot at one of the gates.