He issued gold coins in addition to the existing copper and silver coinage. The Hephthalites issued numerous coins imitating the coinage of Khosrow II. Until 1955, the BWI$ existed only as banknotes in conjunction with sterling fractional coinage. The government of Saint Helena produces its own coinage and banknotes. This is in contrast to coin orientation, which is used in United States coinage. The West Point Mint produces bullion coinage (including proofs). These consisted of deposits, currency exchange, validation of coinage, and loans. In passing the Coinage Act, Congress eliminated bimetallism. The births were celebrated on the imperial coinage. The coinage of various English colonies also circulated. Much of the coinage produced in these mints was nearly worthless. Internally, the empire faced hyperinflation caused by years of coinage devaluation. Minerva is featured on the coinage of different Roman emperors. A new bronze coinage was introduced from 1848. It would also have required the withdrawal and reissuance of the existing copper coinage.