Kipper und Wipper
Kipper und Wipper (German: Kipper- und Wipperzeit, literally "Kipper and Wipper time") was a financial crisis during the start of the Thirty Years' War. While debasing of mint was observed earlier, with the onset of the war the military expenditures rose drastically and the city-states in the Holy Roman Empire began to heavily debase currency in order to raise revenue.