Murray N. Rothbard
Government Meddling With Money
Debasement was the State's method of counterfeiting the very coins it had banned private firms from making in the name of vigorous protection of the monetary standard. Sometimes, the government committed simple fraud, secretly diluting gold with a base alloy, making shortweight coins. More characteristically, the mint melted and recoined all the coins of the realm, giving the subjects back the same number of "pounds" or "marks," but of a lighter weight. The leftover ounces of gold or silver were pocketed by the King and used to pay his expenses. In that way, government continually juggled and redefined the very standard it was pledged to protect. The profits of debasement were haughtily claimed as "seniorage" by the rulers.
Rapid and severe debasement was a hallmark of the Middle Ages, in almost every country in Europe. Thus, in 1200 A.D., the French livre tournois was defined at ninety-eight grams of fine silver; by 1600 A.D. it signified only eleven grams. A striking case is the dinar, a coin of the Saracens in Spain. The dinar originally consisted of sixty-five gold grains, when first coined at the end of the seventh century. The Saracens were notably sound in monetary matters, and by the middle of the twelfth century, the dinar was still sixty grains. At that point, the Christian kings conquered Spain, and by the early thirteenth century, the dinar (now called maravedi) was reduced to fourteen grains. Soon the gold coin was too light to circulate, and it was converted into a silver coin weighing twenty-six grains of silver. This, too, was debased, and by the mid-fifteenth century, the maravedi was only 1.5 silver grains, and again too small to circulate. 
 On debasement, see Elgin Groseclose, Money and Man (New York: Frederick Ungar, 1961), pp. 57-76.