who moved to Oxford in 1922. After working in Cambridge and Sheffield, he returned to Oxford in 1935. There he teamed up with Ernst Chain and by 1939 they succeeded in isolating and purifying penicillin. They also developed a method of producing the drug in large quantities and carried out its first clinical trials. The two men shared the 1945 Nobel Prize for physiology or medicine with penicillin’s discoverer, Alexander Fleming.