The Mongol Invasion
During its fragmentation, Kievan Rus' faced its greatest threat from invading Mongols. An army from Kievan Rus', together with the Turkic Polovtsians, met a Mongol raiding party in 1223 at the Kalka River. The army of Kievan Rus' and its Polovtsian allies were soundly defeated. A much larger Mongol force overran much of Kievan Rus' in the winter of 1237-38. In 1240 the city of Kiev was sacked, and the Mongols moved on to Poland and Hungary. Of the principalities of Kievan Rus', only the Republic of Novgorod escaped the invasion; it did, however, pay tribute to the Mongols. One branch of the Mongols withdrew to Sarai on the lower Volga River and established the Golden Horde (see Glossary). From Sarai the Golden Horde Mongols controlled Kievan Rus', ruling indirectly through its princes and tax collectors.
The impact of the Mongol invasion was uneven. Some centers, Kiev for example, never recovered from the devastation of the initial attack. The Republic of Novgorod continued to prosper unscathed, and a new entity, the city of Moscow, flourished under the Mongols. Although a Russian army defeated the Golden Horde at Kulikovo in 1380, Mongol domination of territories inhabited by Russians, and demands for tribute from Russian princes, continued until about 1480. In the early fourteenth century, however, Lithuania pushed the Mongols from territories inhabited by Ukrainians and Belorussians and claimed these lands. The Lithuanians accepted the Ruthenian language (Ukrainian-Belorussian) as the state language and maintained the judicial and administrative practices of Kievan Rus'. The grand duke of Lithuania became a contender for the political and cultural heritage of Kievan Rus'. Ultimately, the traditions of Kievan Rus' were superseded by Polish influences in Lithuania.
Historians have debated the long-term impact of Mongol rule on Russian and Soviet society. The Mongols have been blamed for the destruction of Kievan Rus'; the breakup of an old "Russian" nationality into Ukrainian, Belorussian, and Russian components; and the introduction of "oriental despotism" to Russia. But most historians have agreed that Kievan Rus' was not a homogeneous political, cultural, or ethnic entity and that the Mongols merely accelerated its breakup, which had begun before the invasion. Nevertheless, modern historians have tended to credit the Mongol regime with a very important role in the development of Muscovy as a state. Muscovy, for example, adopted its postal road network, census, fiscal system, and military organization from the Mongols.
Kievan Rus' left a powerful legacy. Under the leadership of the Rurikid Dynasty, a large territory inhabited by East Slavs was united into an important, albeit unstable, state. After the acceptance of Eastern Orthodoxy, Kievan Rus' was united by a church structure and developed a Byzantine-Slavic synthesis in culture, the arts, and traditions. In the western part of this area, these traditions helped form the Ukrainian and Belorussian nationalities. In the northeastern periphery of Kievan Rus', these traditions were adapted to form the Russian autocratic state