Ludwig Von Mises said this quote

Fiscal considerations have led to the promulgation of a theory that attributes to the minting authority the right to regulate the purchasing power of the coinage as it thinks fit. For just as long as the minting of coins has been a government function, governments have tried to fix the weight and content of the coins as they wished. Philip VI of France expressly claimed the right to mint such money and give it such currency and at such rate as we desire and seems good to us and all medieval rulers thought and did as he in this matter. Obliging jurists supported them by attempts to discover a philosophical basis for the divine right of kings to debase the coinage and to prove that the true value of the coins was that assigned to them by the ruler of the country.