The Reinheitsgebot, also known as the German Beer Purity Law, was originally drafted in 1487 and put into law on April 23rd, 1516 in the city of Ingolstadt, in Bavaria, Germany. The original Reinheitsgebot document stated that the only ingredients that could be used in the production of Bavarian beer were water, barley, and hops. In addition to ingredient restrictions, the document also set pricing standards for the sale of beer. At the time the Reinheitsgebot was drafted, the function of yeast in brewing was not understood, and for that reason it was not listed as an acceptable ingredient in beer.