The famous Swedish chemist Carl Wilhelm Scheele is considered to be one of the most significant scientists of the 18th century and one of the founding fathers of modern chemistry. Scheele was born as the seventh of 11 children in Stralsund on 19 December, 1742. After high school Scheele worked as a pharmacist in Gothenburg before going to Malmö, Uppsala and Stockholm. In 1775 Scheele moved to Köping where he lived until his death on 21 May, 1786. He was elected to membership in the Royal Swedish Academy of Sciences in Stockholm in 1775. His most important achievment was the discovery of oxygen which he described in his main work "Chemische Abhandlung von der Luft und dem Feuer" (Chemical Treatise of Air and Fire; Uppsala und Leipzig, M. Swederus 1777).