In the end the princes of Moscow became supreme. They grew rich, and were able to keep up a regular army, that chief tool of despotism. The crown lands alone gave them dominion over three hundred thousand subjects. The time was coming in which they would be the absolute rulers of all Russia. But before this could be accomplished the power of the khans must be broken, and the first step towards this was taken by the great Dmitri Donskoi, who became grand prince of Moscow in 1362.

Dmitri came to the throne at a fortunate epoch. The Golden Horde was breaking to pieces. There were several khans, at war with one another, and discord ruled among the overlords of Russia. Still greater discord reigned in Russia itself. For eighteen years Dmitri was kept busy in wars with the princes of Tver, Kief, and Lithuania. Terrible was the war with Tver. Four times he overcame Michael, its prince. Four times did Michael, aided by the prince of Lithuania, gain the victory. During this obstinate conflict Moscow was twice besieged. Only its stone walls, lately built, saved it from capture and ruin. At length Olguerd, the fiery prince of Lithuania, died, and Tver yielded. Moscow became paramount among the Russian principalities.

And now Dmitri, with all Russia as his realm, dared to defy the terrible Tartars. For more than a century no Russian prince had ventured to appear before the khan of the Golden Horde except on his knees. Dmitri had thus humbled himself only three years before. Now, inflated with his new power, he refused to pay tribute to the khan, and went so far as to put to death the Tartar envoy, who insolently demanded the accustomed payment.

Dmitri had burned his bridges behind him. He had flung down the gage of war to the Tartars, and would soon feel their hand in all its dreaded strength. The khan, on hearing of the murder of his ambassador, burst into a terrible rage. The civil wars which divided the Golden Horde had for the time ceased, and Mamai, the khan, gathered all the power of the Horde and marched on defiant Moscow, vowing to sweep that rebel city from the face of the earth.

The Russians did not wait his coming. All dissensions ceased in the face of the impending peril, all the princes sent aid, and Dmitri marched to the Don at the head of an army of two hundred thousand men. Here he found the redoubtable Mamai with three times that number of the fierce Tartar horsemen in his train.

"Yonder lies the foe," said Dmitri to his princely associates. "Here runs the Don. Shall we await him here, or cross and meet him with the river at our backs?"

"Let us cross," was the unanimous verdict. "Let us be first in the assault."

At once the order was given, and the battalions marched on board the boats and were ferried across the stream, at a short distance from the opposite bank of which the enemy lay. No sooner had they landed than Dmitri ordered all the boats to be cast adrift. It was to be victory or death; no hope of escape by flight was left; but well he knew that the men would fight with double valor under such desperate straits.

The battle began. On the serried Russian ranks the Tartars poured in that impetuous assault which had so often carried their hosts to victory. The Russians defended themselves with fiery valor, assault after assault was repulsed, and so fiercely was the field contested that multitudes of the fallen were trampled to death beneath the horses' feet. At length, however, numbers began to tell. The Russians grew weary from the closeness of the conflict. The vast host of the Tartars enabled them to replace with fresh troops all that were worn in the fight. Victory seemed about to perch upon their banners.

Dismay crept into the Russian ranks. They would have broken in flight, but no avenue of escape was left. The river ran behind them, unruffled by a boat. Flight meant death by drowning; fight meant death by the sword. Of the two the latter seemed best, for the Russians firmly believed that death at the hands of the infidels meant an immediate transport to the heavenly mansions of bliss.

At this critical moment, when the host of Dmitri was wavering between panic and courage, the men ready to drop their swords through sheer fatigue, an unlooked-for diversion inspired their shrinking souls. The grand prince had stationed a detachment of his army as a reserve, and these, as yet, had taken no part in the battle. Now, fresh and furious, they were brought up, and fell vigorously upon the rear of the Tartars, who, filled with sudden terror, thought that a new army had come to the aid of the old. A moment later they broke and fled, pursued by their triumphant foes, and falling fast as they hurried in panic fear from the encrimsoned field.

Something like amazement filled the souls of the Russians as they saw their dreaded enemies in flight. Such a consummation they had scarcely dared hope for, accustomed as they had been for a century to crouch before this dreadful foe. They had bought their victory dearly. Their dead strewed the ground by thousands. Yet to be victorious over the Tartar host seemed to them an ample recompense for an even greater loss than that sustained. Eight days were occupied by the survivors in burying the slain. As for the Tartar dead, they were left to fester on the field. Such was the great victory of the Don, from which Dmitri gained his honorable surname of Donskoi. He died nine years afterwards (1389), having won the high honor of being the first to vanquish the terrible horsemen of the Steppes, firmly founded the authority of the grand princes, and made Moscow the paramount power in Russia.