Thomas Gresham made a distinction between “good money” and “bad coins. According to his theory, when a depreciated currency is in circulation in parallel with other currencies whose value has not depreciated in relation to that of a precious metal, currencies depreciated and therefore less valuable, will be moving, “good “will save long term, disappear from the transactions. Gresham’s Law was intended particularly to bimetallic monetary systems, but Gresham’s made from the only silver coin of his time: the shillling, distorted by a very significant seigniorage, which had led to the disappearance of shillings cast before this seigniorage. Gresham made his observations on the evil and the good money while in the service of Queen Elizabeth, with respect to the observed poor quality of British coinage.The previous monarchs, Henry VIII and Edward VI, had forced the people to accept debased coins through its laws on legal tender. Gresham also made his comparison of good and bad money when the precious metal in the coin was the same, but not compared with gold silver or gold with paper money. While the theory was attributed to Gresham, the law is, in fact, older: Nicolas Oresme proved its mechanism in 1371 and had already evoked Aristophanes in his comedy The Frogs. Another predecessor was the treaty monetae cudendae ratio (1519) by Nicolas Copernicus, in which Copernicus wrote that “bad (debased) money out of circulation leads to good (not debased) money.”