Own silver deposits were discovered in Russia only in the 18th century, therefore the country's monetary economy depended entirely on the influx of this metal, primarily in the form of a coin, from abroad. In the 12th century, this influx began to shorten from the western direction (presumably due to the strengthening of the German knight orders in the Baltic States and the beginning of regular hostilities between them and the western principalities; see the article “Ostsiedlung”), and in the 13th century from the eastern (presumably, this was caused by the Tatar-Mongol invasion).