15 republics of the Soviet Union. History Imperial ruble From the 14th to the 17th centuries the ruble was neither a coin nor a currency but rather a unit of weight. The most used currency was a small silver coin called denga (pl. dengi). There were two variants of the denga, minted in Novgorod and Moscow. The weight of a denga silver coin was unstable and inflating, but by 1535 one Novgorod denga weighed , the Moscow denga being a half that of the Novgorod denga. Thus one account ruble consisted of 100 Novgorod or 200 Moscow dengi ( of silver). As the Novgorod denga bore the image of a rider with a spear (), it later has become known as kopek. In the 17th century, the weight of a kopek coin reduced to , thus one ruble was equal to of silver. In 1654–1655 tsar Alexis I tried to carry out a monetary reform and ordered the mintage of silver one ruble coins from imported joachimsthalers and new kopek coins from copper (old silver kopeks were left in circulation). Although around 1 million of such rubles was made, its lower weight (28–32 grams) against the nominal ruble (48 g) led to counterfeiting, speculation and inflation, and after the Copper Riot of 1662 the new monetary system was abandoned in favour of the old one. Russian Empire In 1704 Peter the Great finally reformed the old Russian monetary system, minting a silver ruble coin of weight and 72% fineness; hence 20.22 g fine silver. The decision to subdivide it primarily into 100 copper kopeks, rather than 200 Muscovite denga, made the Russian ruble the world's first decimal currency. The amount of silver in a ruble varied in the 18th century. Additionally, coins worth over a ruble were minted in gold and platinum. By the end of the 18th century, the ruble was set to 4 zolotnik 21 dolya (or 4 zolotnik, almost exactly equal to 18 grams) of pure silver or 27 dolya (almost exactly equal to ) of pure gold, with a ratio of 15:1 for the values of the two metals. In 1828, platinum coins were introduced with 1 ruble equal to 77 dolya (3.451 grams). On 17 December 1885, a new standard was adopted which did not change the silver ruble but reduced the gold content to 1.161 grams, pegging the gold ruble to the French franc