France’s role as a wine producer had been gravely affected by the viticultural devastation caused by powdery mildew, downy mildew, and phylloxera in the second half of the 19th century (see france, history). Fine wines were available in much-reduced quantity, but the languedoc and algeria had become vast factories for the production of very ordinary wine at very low prices. Laws passed in the first two decades of the 20th century were aimed at bringing an end to the adulteration and fraud that was by then widespread. These were based simply on the principle of geographical delimitation, and specified particular areas within which certain wines had to be produced. Bordeaux, Banyuls, and Clairette de Die were among the first; disagreement about exactly which districts should be allowed to produce France’s most famous sparkling wine led to riots (see champagne, history).