Alongside silver and gold, copper is the third typical minting metal, an integral part of many of the coinage systems of Greek and Roman antiquity. In medieval Europe, however, silver currency prevailed, supplemented by gold from the 13th century onwards; copper served as an additive to the silver alloy, which could lead to crises when misused. Between the 16th and 18th centuries, copper became established across Europe as the material of the lowest denominations (token coins). In Germany, there was a first copper boom during the Kipper and Wipper period (1618-1622), but it did not take hold until the 18th century. This was different in Westphalia: here, in the 16th and 17th centuries, country towns minted copper coins only; this credit money had advantages, but also disadvantages, and many a sovereign took this as an example. The paper will emphasize this special impact of Westphalia on to the development of the trimetallic coinage system in Germany.