At times hybrid monetary systems were used. Constantina Katsari has argued that principles from both metallism and chartalism were reflected in the monetary system introduced by Augustus, which was used in the eastern provinces of the Roman Empire from the early 1st century to the late 3rd century AD. Monometallism versus bimetallism A smaller disagreement which takes place relating to metallism is whether one metal should be used as currency (as in monometallism), or should there be two or more metals for that purpose (as in bimetallism). History of metallic monetary systems Historically, silver has been the main kind of money around the world, circulating bimetallically with gold. In many languages, the words for "money" and "silver" are identical. In the final era of global metal-based money, i.e. the first quarter of the 20th century, monometallic gold use has been the standard. Broad sense of the term In the broad sense of the term, which tends to be used only by scholars, metallism considers money to be a "creature of the market", a means to facilitate exchange of goods and services. In this broad sense, the essential nature of money is purchasing power, and it does not necessarily need to be backed by metals. Understood in this broad sense, metallism reflects the majority view among mainstream economists, which has prevailed since the early 19th century. See also Bimetallism Bullionism Bullion Bullion coin Commodity money Inflation Inflationism Inflation hedge Monetary policy Precious metals Silverite Modern Monetary Theory References Further reading David Fields & Matías Vernengo (2011). Hegemonic Currencies during the Crisis: The Dollar versus the Euro in a Cartalist Perspective. Levy Economics Institute Working Paper No. 666. David Fields & Matías Vernengo (2012): Hegemonic currencies during the crisis: The dollar versus the euro in a Cartalist perspective, Review of International Political Economy, DOI:10.1080/09692290.2012.698997 Metallism Monetary economics