The manners of the barbarian Mogols had, for some time, been assuming a marked change.  They emerged from their native wilds as fierce and untamed as wolves.  The herds of cattle they drove along with them supplied them with food, and the skins of these animals supplied them with clothing and with tents.  Their home was wherever they happened to be encamped, but, having reached the banks of the Black Sea and the fertile valleys of the Volga and the Don, they became acquainted with the luxuries of Europe and of the more civilized portions of Asia.  Commerce enriched them.  Large cities were erected, embellished by the genius of Grecian and Italian architects.  Life became more desirable, and the wealthy chieftains, indulging in luxury, were less eager to encounter the exposure and perils of battle.  The love of wealth now became with them a ruling passion.  For gold they would grant any favors.  The golden promises of Simeon completely won the heart of Usbeck, and the young prince returned to Moscow flushed with success.  He assumed such airs of superiority and of power as secured for him the title of The Superb.  He caused himself to be crowned king, with much religious pomp, in the cathedral of Vladimir.  Novgorod manifested some resistance to his assumptions.  He instantly invaded the principality, hewed down all opposition, and punished his opponents with such severity that there was a simultaneous cry for mercy.  Rapidly he extended his power, and the fragmentary principalities of Russia began again to assume the aspect of concentration and adhesion.

Ere two years had elapsed, Usbeck, the khan, died.  This remarkable man had been, for some time, the friend and the ally of Pope Benoit XII., who had hoped to convert him to the Christian religion.  The khan had even allowed the pope to introduce Christianity to the Tartar territories bordering on the Black Sea.  Tchanibek, the oldest son of Usbeck, upon the death of his father, assassinated his brothers, and thus attained the supreme authority.  He was a zealous Mohammedan, and commenced his reign by commanding all the princes of the principalities of Russia to hasten to the horde and prostrate themselves, in token of homage, before his throne.  The least delay would subject the offender to confiscation and death.  Simeon was one of the first to do homage to the new khan.  He was received with great favor, and dismissed confirmed in all his privileges.

In the year 1346, one of the most desolating plagues recorded in history, commenced its ravages in China, and swept over all Asia and nearly all Europe.  The disease is recorded in the ancient annals under the name of Black Death.  Thirteen millions of the population were, in the course of a few months, swept into the grave.  Entire cities were depopulated, and the dead by thousands lay unburied.  The pestilence swept with terrible fury the encampments of the Tartars, and weakened that despotic power beyond all recovery.  But one third of the population of the principalities of Pskof and of Novgorod were left living.  At London fifty thousand were interred in a single cemetery.  The disease commenced with swellings on the fleshy parts of the body, a violent spitting of blood ensued, which was followed by death the second or third day.