During Murad's reign he extended his domain to the Balkans and up to the very walls of the imperial city; whilst the unhappy Emperor without an empire was thankful to escape for the present by acknowledging his supremacy, and even by taking up arms at his command against one of his own free towns.
For the next hundred and fifty years the Ottomans were only hindered from the invasion of Christendom by the determined action of the Servians and Hungarians. And meantime the chance of freeing the Greek Empire altogether from Ottoman rule had come and gone.
In 1402, when the Turkish Sultan Bajazet was pressing hard upon Constantinople, the great Tamerlane, chief of the Tartar hordes, who had already conquered Persia, Turkestan, Russia, and India, came down like a thunderbolt upon the ambitious plans of Bajazet. The latter defied the conqueror, saying, "Thy armies are innumerable? Be they so! But what are the arrows of the flying Tartar against the scimitars and battle-axes of my firm and invincible Janissaries?"
Alike in their religious faith and in their ambitions, these two men now became deadly rivals; but not even the "New Army" of the Ottoman could stand against the Tartar hordes.
One city after another fell and was sacked; Bajazet himself was taken, and imprisoned, according to one story, in an iron cage. Another and more modern version says that the great Tamerlane treated his captive with the utmost courtesy and consideration; and on the occasion of the victorious feast after the battle, placed a crown upon his head and a sceptre in his hand, promising that he should return to the throne of his fathers with greater glory than before. But Bajazet died before his generous conqueror could carry out his promises, and Tamerlane, taking his place, demanded tribute of his sons and of Manuel of Constantinople at the same time.
The two elder sons of Bajazet were now at variance over the poor remains of his empire. One of these bought the aid of Manuel by surrendering the coast of Thessaly and the seaports of the Black Sea, and the Emperor was able to keep these just so long as the war between the brothers continued to rage. Even after this had ended in the triumph over both of Mohammed, Bajazet's youngest son, Manuel could feel fairly safe, for of late years he had thrown in his lot with Mohammed and was allowed to hold his possessions in peace.
This period of civil war, was of course, the opportunity for the Greek ruler to have driven out the Ottomans from his former empire. But this opportunity was lost as so many others had been, and after Mohammed died in 1421, the empire was entirely surrendered to the Ottomans.
Mohammed's successor, Amurath, is thus described by one of his own historians. "He was a just and valiant prince, of a great soul, patient of labours, learned, merciful, religious, charitable; a lover and encourager of the studious, and of all who excelled in any art or science; a good Emperor and a great general.
"No man obtained more or greater victories than Amurath. Under his reign the soldier was ever victorious, the citizen rich and secure. If he subdued any country, his first care was to build mosques and caravanserais, hospitals and colleges. Every year he gave a thousand pieces of gold to the sons of the Prophet, and sent two thousands five hundred to the religious persons of Mecca, Medina and Jerusalem."
Like the Emperor Charles V, a century later, this "perfect prince" laid down the reins of empire at the very height of his glory and "retired to the society of saints and hermits," at Magnesia. Twice he was recalled to the field of action, first by an invasion of the Hungarians, the second time by the insurrection of the "haughty Janissaries "; and with these latter, now humbled and trembling at his very look, the great Amurath remained until his death.