After the Mongols ravaged the Bolğar and Bilär territories in the 13th century, the surviving Bulgars recovered in numbers and a small number of Kipchaks were assimilated from which they adopted their language (the so-called Bulgarism), or Kipchaks and Bulgars mixed to create a modern Kazan-Tatar population. Some Tatars also went to Lithuania, brought by Vytautas the great. Kazan became the center of the Principality, which was dependent on The Golden Horde. In the 13th and 14th centuries, Kazan was growing, becoming an important trade and political center within The Golden Horde. The growth of the city was also promoted by the successful geographical location at the intersection of major trade routes connecting East and West. During the same period, the minting of currency began with the indication of the place of minting—"Bulgar al-Jadid", that is, a New Bulgar.