From 1862 to 1879, United States Notes were legal tender and the dominant paper currency but were not convertible at face value into gold and traded at a discount. However some transactions, such as customs duties and interest on the federal debt, were required to be made in gold. Thus the early gold certificates were acceptable in some transactions where United States Notes were not, but were not used in general circulation due to their premium value. After 1879, the government was willing to redeem United States Notes at face value in gold, bringing the United States Notes into parity with gold certificates, making the latter also a candidate for general circulation.