The study proposes a scientific view on development of Russia in Mongol period, which differs from the modern mainstream of Russian science. The hypothesis is put forward that Russia has lagged behind West in the technical and political aspects before the Mongol conquest. Russian princedoms suffered from a rarity of the population. The level of military affairs in the Russian States was lower as on West and in Mongolia. Mongolian conquest resulted in an outflow of money capital and the decline of crafts in Russia. Russia was included into the economy of Mongolian Empire as a supplier of fur and an importer of manufactured goods. The strengthening of the Moscow Principality in the XIV century became as result of economic and military trends in Eastern Russia and Golden Horde, in particular the decline of neighboring principalities.