When they debased Gold

For 99% of recorded history, emperors, kings, and parliaments "struggled" with the limitations of gold. If Henry VIII, for instance, wanted to spend money to stimulate the English economy, he had a few choices as to where to get the gold: tax his citizenry, borrow from the bankers in Holland, dig for gold in his own realm, or seek to plunder gold from foreign sources through war or blackmail. All of these options involved significant costs and pitfalls. Henry's easiest means to expand his money supply was to debase his gold by secretly mixing in base-metal alloys. However, such a ruse was easily detected by sophisticated market participants, who would subsequently shun Henry's coinage. The result was that the governments of the world could only spend what they had.
Despite these "limitations", the global economy expanded significantly over the centuries. The march from ancient, to medieval, to renaissance, and ultimately to industrial economies occurred without the ability to easily or rapidly expand money supplies. This is because the key to economic growth is not to push up aggregate demand, as the Keynesians would argue, but to increase the efficiency and amount of goods produced. As a result, despite wars, pestilence, natural disasters, and famines, the general march of economics had always been upward. During that time, money generally increased in value as greater efficiency expanded the number of goods that a given weight of gold could buy.
But modern economists tend to ignore the period of history before the Great Depression - which is, in fact, most of history - and instead focus solely on the period since the supply of non-gold "fiat" money has been expanded at will. Although the drift began before the Second World War (with the devaluations of the Roosevelt Administration), the end did not come until 1971, when President Nixon officially dissolved the linkage between the U.S. dollar (the world's reserve currency) and gold. Since that time, the supply of U.S. dollars has expanded exponentially and has resulted in the currency losing more than 80% of its value.
Peter D. Schiff