From Bokhara he advanced to Samarcande. This city was strongly fortified, and contained a hundred thousand soldiers within its walls, besides an immense number of elephants trained to fight. The city was soon taken. Thirty thousand were slain, and thirty thousand carried into perpetual slavery. All the adjacent cities soon shared a similar fate. For three years the armies of Genghis Khan ravaged the whole country between the Aral lake and the Indus, with such fearful devastation that for six hundred years the region did not recover from the calamity. Mahomet II., pursued by his indefatigable foe, fled to one of the islands of the Caspian Sea, where he perished in paroxysms of rage and despair. Genghis Khan having thoroughly subdued this whole region, now sent a division of his army, under two of his most distinguished generals, across the Caspian Sea to subjugate the regions on the western shore. Here, as before, victory accompanied their standards, and, with merciless severity, they swept the whole country to the sea of Azof. The tidings of their advance, so bloody, so resistless, spread into Russia, exciting universal terror. The conquerors, elated with success, rushed on over the plains of Russia, and were already pouring down into the valley of the Dnieper. Mstislaf, prince of Galitch, already so renowned for his warlike exploits, was eager to measure arms with those soldiers, the terror of whose ravages now filled the world. He hurriedly assembled all the neighboring princes at Kief, and urged immediate and vigorous cooeperation to repel the common foe. The Russian army was promptly rendezvoused on the banks of the Dnieper, preparatory to its march. Another large army was collected by the Russian princes who inhabited the valley of the Dniester. In a thousand barges they descended the river to the Black Sea. Then entering the Dnieper they ascended the stream to unite with the main army waiting impatiently their arrival.