The Mongolian military leader Batu Khan (died 1255) conquered Russia and the adjoining territories of eastern Europe and organized the Mongol state known as the Golden Horde.

Batu was a grandson of Genghis Khan, the conqueror of Asia and founder of the Mongol Empire. Batu early showed a talent for military and administrative affairs and distinguished himself in the service of his father, Juchi, who had been entrusted with the administration and expansion of the western section of the empire, then comprising the territory of central Asia and western Siberia. Following Juchi's death in 1227, this task fell to Batu.

Although the Mongols had defeated the Russians in a battle on the Kalka River in 1223, a serious attempt to conquer Russia, and perhaps Europe, was not undertaken until 1237. Exploiting disunity among Russian princes, Batu conquered their territories with unequaled brutality, and by 1241 all of Russia was under his control. While one of his armies proceeded as far west as Liegnitz (Legnica) in Silesia, where it defeated a combined force of Poles and Germans, Batu himself crossed the Carpathian Mountains and the Danubian plains to the Adriatic Sea and concentrated his forces in Hungary for a campaign against western Europe through the Danube valley. Upon receiving news of the death of Great Khan Ugedey (Ögödei), however, Batu decided to return to the east and withdrew his armies to the Volga River, subjugating Bulgaria, Wallachia, Moldavia, and the Cuman khanate in the Pontic steppes along the way (1242).

Having failed to obtain the title of Great Khan of Mongolia for himself or his ally Mongka (Möngkë, Mangu), Batu settled in the city of Saray on the lower Volga and attended to the administration of his own domain, which now extended from the Ob River in western Siberia to Poland and Bulgaria in eastern Europe and which came to be called the Golden Horde. In 1251, when Mongka finally became great khan, Batu received from him a recognition of complete autonomy.

At first brutal and irreconcilable in his treatment of the conquered lands, Batu grew tolerant and accommodating with age, allowing local native princes to rule their lands at their will as long as they remained loyal to him and regularly paid him the tribute collected among their subjects. He died in 1255, but his empire survived until the end of the 15th century.