The next step was the conquest of the imperial city on the Bosphorus. This could not be effected without a fleet; neither Thessalonika nor Constantinople could be taken as long as their ports were open. Douchan turned to the Venetians for help, but they refused to encourage the formation of a new great power on the Mediterranean. Besides, the Turks now barred the way, for Gallipoli had been garrisoned. The Osmanlis, therefore, held the key to the Dardanelles. Undeterred, however, by these changes, Douchan girded himself for a final attack on Constantinople, when death overtook him suddenly on the 20th of December, 1355.

His successor, Ourach, was only nineteen years old, a young man of mild character, with none of the stern qualities needed to carry out the warlike plans of his father. His vassal lords had not lived long enough under a centralized system to understand its advantages even under a weak ruler. Without the strong personality of Douchan, the empire and the titular dignity of Tsar were only shadows. Less fortunate than the tribe of Osman, where the line from father to son maintained in unbroken succession under strong personal rule the clear-sighted aims of the founder, the Servians could not resist the forces of disintegration. Their country was mountainous, and hence the people were kept apart in small, isolated communities. There was no longer a vigorous leader to resist the centrifugal tendencies imposed by petty ambitions and jealousies; and only for ten years after Douchan’s death did the external form of his empire last. As a barrier against the Turkish conquerors in Europe the Servians proved utterly ineffective.

With the Slavs eliminated the brunt of resistance naturally fell upon the Greeks; but they were now only an emaciated remnant of a great and long enduring empire that had worn out the Arab and Saracen and had held the Slav at bay. After the fall of the Latin rule at Constantinople (1261), the city became the capital of the reconstructed Eastern Empire; but the scale of this restoration was much reduced from its original grandeur. There were four groups of imperial territories: the Asiatic possessions that had been controlled from Nicæa, economically important as trade centers, but not great in extent; in Europe, the capital and Thrace; some towns to the North, such as Adrianople, a part of Macedonia, the peninsula of Gallipoli, Chalcidice, and a part of Thessaly; certain islands in the Ægean, Rhodes, Lesbos, Samothrace, Imbros, and the Peloponnesus in Greece.

These possessions, the feeble remnants of the realm once ruled by Basil the Macedonian, were surrounded by lands inhabited by numerous races. There were the Frankish lands in Greece, the Venetians in the Ægean, an independent Greek sovereignty in Epirus, Catalans in Thessaly, Genoese in the Black and Ægean Seas, and the parts immediately adjacent to Constantinople itself; the Seldjouk sultans at Iconium, and the autonomous empire of Trebizond. There were also the Slavic peoples in the Balkan peninsula, not to mention the more distant Christian kingdoms of Armenia and Georgia.

As a military power the revived Greek Empire was pathetically feeble. Its last great leader in war was Michael VIII, who had retaken Constantinople from the Latins, a conquest on a slight scale, since the Latins were even weaker than their opponents. The measure of Greek offensive is attested by the inability of any Greek Emperor to retake the Asiatic provinces from the Turk, to annex the Empire of Trebizond, to resist the Slavs in the Balkans, or to reoccupy the islands of the Ægean and drive the Franks from Greece. Even in the interior there was no effective administration. In every Greek city there were colonies of Italian merchants, either Genoese or Venetian, who formed independent communities under their own podestà. The army was filled with foreign contingents, who were not even mercenary troops, because the Empire could not afford to hire soldiers. They were auxiliary forces, organized as complete military units under their own natural chief, and were a constant menace. When they saw fit, they pillaged the country and sometimes fought among themselves. They were under no kind of control from the central or local authorities; within their own camps on the frontiers, in the provinces, even under the walls of the capital itself, they obeyed their own commanders and not the Emperor.

One of the most radical changes for the worse in the revived Greek Empire, a change that marked the contrast with the heroic period of Byzantine military enterprise, was the lack of a fleet. For his naval operations the Emperor depended on the Venetians or Genoese, a most unsatisfactory arrangement, for, owing to the jealousy of these two commercial states, if one were the ally of Constantinople, the other was certain to be on the opposite side. In 1296 the Venetians, after defeating their rivals at sea, laid siege to the Pera and Galata sections of Constantinople, the seat of the Genoese colony, and in setting fire to the quarter destroyed many Greek houses. Later on, the Genoese revenged themselves by massacring the Venetian residents of Constantinople.

The anarchy was increased when, owing to rival claimants to the throne, open civil war broke out, as it did frequently in the course of the fourteenth century. Cantacuzene, an official in the imperial palace, who became rival Emperor, while Anna of Saxony was regent during the minority of her son, John V, after the death of his father, Andronicus III, allied himself with the Servians and with the Seldjouk emir of Konia. Anna tried to strengthen her side by calling upon Ourkhan, the Osmanli Sultan. In the war that followed the Turks were authorized to seize the citizens of the empire, and the rival governments placed at the disposition of their Mohammedan allies seaports and vessels. The captives taken were sent to Asia and sold as slaves in the Turkish emirates.

The various enemies of the Empire used this time of civil strife as a favorable opportunity for seizing its territory. Stephen Douchan conquered and annexed most of Macedonia, and, as their part of the spoil, the Genoese acquired Chios and commenced a blockade of Constantinople, the defense of which was intrusted to other Italians under the command of Facciolati. This leader deserted the cause of the regent Anna, and admitted Cantacuzene into the capital. An arrangement was now patched up by which Cantacuzene was to be Emperor until John V reached the age of twenty-five years.

Even now Cantacuzene’s troubles as ruler were not over; his plan to form an independent navy recruited from his own subjects and his desire to do away with the commercial monopoly of the Genoese led to a war of five years, 1348-1352. Cantacuzene’s Venetian allies were defeated under the walls of Constantinople, with the result that the Greek Emperor was obliged to make peace under most disadvantageous terms. Not long after this disaster civil war broke out again. Souliman, Ourkhan’s son, was a subsidized ally of Cantacuzene, and thousands of the inhabitants of the Empire were deported by the Turks to be sold as slaves.

The lessons of these wars were not lost upon the Turkish auxiliaries who were allowed to play such a conspicuous and decisive rôle by both sides; they became acquainted with the country in which they had served, knew its roads, cities, and inhabitants. All this information was put to good use by them when they crossed the Bosphorus to fight for their own interests and to dispossess their former employers at Constantinople.