German beer labels always carry the inscription "Gebraut nach dem deutschen Reinheitsgebot" or "Gebraut nach dem Bayerischen Reinheitsgebot von 1516" (brewed according to the German Purity Law or the Bavarian Purity Law of 1516). This "beer purity" law is one of the most remarkable and perhaps most misunderstood pieces of legislation. The original law was a ducal decree issued on April 23, 1516, by the Bavarian co-rulers Duke Wilhelm IV and Duke Ludwig X (below). It was introduced at a meeting of an assembly of the Estates of Bavaria, at Ingolstadt, some 60 miles north of Munich. Initially only in feudal Bavaria, but later in all of Germany, the Reinheitsgebot gave government the tools to regulate the ingredients, processes and quality of beer sold to the public (and to levy taxes on beer!). The Reinheitsgebot is the oldest, still valid food safety law in the world.