Tuscany participated in the Wars of Castro (the last time Medicean Tuscany proper was involved in a conflict) and inflicted a defeat on the forces of Pope Urban VIII in 1643. The war effort was costly and the treasury so empty because of it that when the Castro mercenaries were paid for, the state could no longer afford to pay interest on government bonds, with the result that the interest rate was lowered by 0.75%. At that time, the economy was so decrepit that barter trade became prevalent in rural market places.