In Goethe’s masterpiece, the devil Mephistopheles offers an emperor the tantalising vision of limitless wealth through the printing of paper money. There were failed experiments with paper money in 14th-century China, 17th-century Sweden and 18th-century France, to mention just a few. Similarly, in the 1750s and 1760s, the Swedish government issued non-redeemable paper money to pay its war debts. Its departure from the metal standard in 1797, amid the financial pressures of the Anglo–French war, did not produce a collapse of the nation’s paper currency. Paper currency works when people trust it, knowing that it has been valued and accepted by others in the past, and will be valued and accepted in the future.