Rocco is partially right, the Mongols that invaded Kievan Rus were Muslim.
They invaded from what is today Uzbekistan, they converted to Islam to better control Persia. The events of the late 14th Century robbed Russia of a Renaissance. The Duchy of Muscovy had become strong and wealthy, Prince Dmitri took the opportunity to gain freedom by challenging the dominance of the Kazan Khanate. The ensuing war was extremely bloody, but eventually he did manage to take Kazan. He declared the new Kingdom of Russia just as the Timurid Mongols showed up. With his armies decimated, Dmitri had no choice but to submit. The Golden Horde was established with a new capital at the more defensive Sevastopol in Crimea.