It was sometimes one of the ingredients in gruit, traditionally used in beers as a flavouring. Several cities, most notable Pilsen, were named after its German name form "Bilsenkraut" in context of the production for beer flavouring.[10] It fell out of usage for beer when it was replaced by hops in the 11th to 16th centuries, as the Bavarian Purity Law of 1516 outlawed ingredients other than barley, hops, yeast, and water.[11]