John, at the age of sixteen, with another daughter of Cantacuzene. Orchan, in pursuance of his agreement with the new Emperor, was married in 1346 at the ripe age of sixty-two to the young Theodora, who was to be allowed to remain a Christian.

It may be assumed that the six thousand soldiers lent to Cantacuzene returned to Asia. But the loan of them soon became a precedent for other transactions of the same kind. In 1349 the Serbians, under Stephen Dushan, were seriously threatening Salonika, and had ultimate designs on Constantinople itself. Orchan was again appealed to for aid by the two Emperors, his father-in-law and brother-in-law, and at their instance he sent twenty thousand soldiers into Europe for the relief of Salonika. With their aid Cantacuzene was able to defeat the Serbians, and to extinguish for ever their hope of replacing the Byzantine Empire at Constantinople. On this occasion, again, it appears that the Ottoman troops, having effected their purpose, returned to Asia. But four years later another opportunity befell Orchan of sending troops across the Straits, and this time of effecting a permanent lodgment in Europe. Cantacuzene, not satisfied with being only a co-Emperor with his son-in-law and the Empress Anna, attempted, in 1353, to usurp the supreme power in the State. His son-in-law, John Palæologus, now of full age, strongly opposed this. Civil war again broke out. For a third time Cantacuzene appealed to his son-in-law Orchan for aid. In return for the loan of twenty thousand soldiers he offered to hand over to the Ottomans a fortress on the European side of the Hellespont. Orchan agreed to this. The Ottoman soldiers were sent into Europe, under Solyman, and were employed by Cantacuzene in fighting against his other son-in-law, the co-Emperor John. They were successful in this, and occupied Demotika. Meanwhile the insignificant fortress of Tzympe was handed over to Orchan and was occupied by Ottoman troops with the full consent of Cantacuzene.

Shortly after this an earthquake occurred in the Thracian Chersonese—not an unfrequent event there. It did great damage to many cities, among others to Gallipoli, the most important fortress on the European side of the Hellespont, and at no great distance from Tzympe. Its walls and ramparts were in great part tumbled down and destroyed, so that entrance to it was made easy. The Ottoman troops at the neighbouring Tzympe, under Solyman, when this opportunity was afforded to them of getting possession of such an important fortress, determined to avail themselves of it. The Greek garrison of Gallipoli, under the belief that the earthquake and the tumbling down of the walls indicated the Divine will, made no resistance, and the Ottomans established themselves there without opposition. Cantacuzene complained of this to Orchan as a gross breach of their treaty, and demanded that Gallipoli should be restored to him. He offered also to pay a fair price for Tzympe. Orchan, though willing enough to take money for Tzympe, refused point-blank to give up Gallipoli. “God,” he said, “having manifested His will in my favour by causing the ramparts to fall, my troops have taken possession of the city, penetrated with thanks to Allah.” It will be seen that Greeks and Turks took the same view of the Divine intervention, the one to excuse their failure to defend the fortress, the other to justify their seizure of it.

This action of Orchan roused great indignation at Constantinople. Cantacuzene now began to see how grave an error he had committed when inviting the Turks into Europe. Public opinion compelled him to declare war against Orchan. He appealed to the Czars of Serbia and Bulgaria to assist him in driving the Ottomans back to Asia. They flatly refused to do so. The Czar of Bulgaria replied: “Three years ago I remonstrated with you for your unholy alliance with the Turks. Now that the storm has burst, let the Byzantines weather it. If the Turks come against me we shall know how to defend ourselves”—a very unfortunate prediction as events ultimately proved! The whole course of history might have been altered if these two Balkan States had joined with the Byzantines in preventing this lodgment of the Turks in Europe. Want of union of the Christian Powers was then, as on many other later occasions, mainly responsible for the extension of the Ottoman Empire in that continent.

Cantacuzene was soon to reap the just reward for his treachery to his country. So far everything had gone well with him. He had ousted the Palæologi from the throne, of which, it must be admitted, they were quite unworthy. He had proclaimed his son Matthew as co-Emperor with himself. But when the full effect of his policy of inviting the Turks into Europe was understood there was a revulsion of feeling against him at Constantinople. The Greek Patriarch refused to crown Matthew. A revolution took place in the city. Cantacuzene found himself without friends. He was everywhere accused of having betrayed the Empire to the Turks. He was compelled to abdicate. He became a monk and retired to a monastery in Greece. He spent the remaining thirty years of his life in seclusion there, and in writing a history of his times, which, though very unreliable, tells enough of his own misdeeds to justify the conclusion that, by inviting the Ottomans into Europe, he proved to be a traitor to his country. The Empress Irene, his wife, became a nun.

John Palæologus was recalled by the people of Constantinople, and, after defeating Matthew, not without difficulty, was established there as sole Emperor. His reign lasted for fifty years, a period full of misfortune for the Empire. He was no more able to compel or induce the Turks to evacuate Europe and return to Asia than his father-in-law. The twenty thousand soldiers who had been invited to Europe by Cantacuzene remained there as enemies of the State they had come to assist. Under the command of Solyman, they advanced into Thrace and captured Tchorlu, within a few miles of Constantinople. Though the occupation of this city and of Demotika was only temporary, the Ottomans firmly established themselves in the southern part of Thrace. The Emperor John was eventually compelled to sign a treaty with Orchan, which recognized these Ottoman conquests in Thrace. Thenceforth the Byzantine Empire became subservient to, and almost the vassal of, the Ottoman Sultan. Solyman brought over from Asia many colonies of Turks and settled them in the Thracian Chersonese and other parts of Thrace.

In 1358 Solyman, who had shown great capacity when in command of the Ottoman army, met with his death by a fall from his horse when engaged in his favourite sport of falconry. His father, Orchan, died in the following year at the age of seventy-two. He had enormously increased the Ottoman dominions. He had achieved the first great object of his ambition, that of driving the Byzantines from their remaining possessions in Asia. He had rounded off his boundaries in the north-west corner of Anatolia by annexing Mysia. He had invaded Europe and had extended Ottoman rule over a part of Thrace. He had reduced the Byzantine Emperor almost to vassalage. These great results had been achieved not so much by force of arms as a general, for he is not credited with any great victory in the field, or by successful assaults on any great fortresses, as by crafty diplomacy and intrigue, backed up by superior force, and by taking advantage of the feebleness and treachery of the Byzantines. He also forged the military weapon by which his son, Murad, was able to effect far greater territorial conquests, both in Europe and Asia.