In 1259 Mongols led by Burundai and Nogai Khan ravaged the principality of Halych-Volynia, Lithuania and Poland. After that Pope Alexander IV tried without success to create a Crusade against the Tartars.
In the 14th century, Khan Tokhtamysh combined the Blue and White Hordes forming the Golden Horde. It seemed that the power of the Golden Horde had begun to rise, but in 1389, Tokhtamysh made the disastrous decision of waging war on his former master, the great Tamerlane. Tamerlane's hordes rampaged through southern Russia, crippling the Golden Horde's economy and practically wiping out its defenses in those lands.
After losing the war, Tokhtamysh was then dethroned by the party of Khan Temur Kutlugh and Emir Edigu, supported by Tamerlane. When Tokhtamysh asked Vytautas the Great for assistance in retaking the Horde, the latter readily gathered a huge army which included Lithuanians, Ruthenians, Russians, Mongols, Moldavians, Poles, Romanians and Teutonic Knights.
In 1398, the huge army moved from Moldavia and conquered the southern steppe all the way to the Dnieper River and northern Crimea. Inspired by their great successes, Vytautas declared a 'Crusade against the Tartars' with Papal backing. Thus, in 1399, the army of Vytautas once again moved on the Horde. His army met the Horde's at the Vorskla River, slightly inside Lithuanian territory.
Although the Lithuanian army was well equipped with cannon, it could not resist a rear attack from Edigu's reserve units. Vytautas hardly escaped alive. Many princes of his kin—possibly as many as 20—were killed (for example, Stefan Musat, Prince of Moldavia and two of his brothers, while a fourth was badly injured), and the victorious Tartars besieged Kiev. "And the Christian blood flowed like water, up to the Kievan walls," as one chronicler put it. Meanwhile, Temur Kutlugh died from the wounds received in the battle, and Tokhtamysh was killed by one of his own men.