at a rate of 1 ruble = 4 francs. This rate was revised in 1897 to 1 ruble = 2 francs (17.424 dolya or 0.77424 g fine gold). This ruble was worth about US$0.5145 in 1914. With the outbreak of World War I, the gold standard peg was dropped and the ruble fell in value, suffering from hyperinflation in the early 1920s. With the founding of the Soviet Union in 1922, the Russian ruble was replaced by the Soviet ruble. The pre-revolutionary Chervonetz was temporarily brought back into circulation from 1922 to 1925. Russia's coins By the beginning of the 19th century, copper coins were issued for , , 1, 2 and 5 kopeks, with silver 5, 10, 25 and 50 kopeks and 1 ruble and gold 5 although production of the 10 ruble coin ceased in 1806. Silver 20 kopeks were introduced in 1820, followed by copper 10 kopeks minted between 1830 and 1839, and copper 3 kopeks introduced in 1840. Between 1828 and 1845, platinum 3, 6 and 12 rubles were issued. In 1860, silver 15 kopeks were introduced, due to the use of this denomination (equal to 1 złoty) in Poland, whilst, in 1869, gold 3 rubles were introduced. In 1886, a new gold coinage was introduced consisting of 5 and 10 ruble coins. This was followed by another in 1897. In addition to smaller 5 and 10 ruble coins, and 15 ruble coins were issued for a single year, as these were equal in size to the previous 5 and 10 ruble coins. The gold coinage was suspended in 1911, with the other denominations produced until the First World War. Constantine ruble The Constantine ruble (Russian: , ) is a rare silver coin of the Russian Empire bearing the profile of Constantine, the brother of emperors Alexander I and Nicholas I. Its manufacture was being prepared at the Saint Petersburg Mint during the brief Interregnum of 1825, but it was never minted in numbers, and never circulated in public. Its existence became known in 1857 in foreign publications. Banknotes Imperial issues In 1768, during the reign of Catherine the Great, the Assignation Bank was instituted to issue the government paper money. It opened in Saint Petersburg and in Moscow in 1769. In 1769, Assignation rubles were introduced for 25, 50, 75 and 100 rubles, with 5 and 10 rubles added in 1787 and 200 rubles in