Both Hahn and Meitner had been nominated for the chemistry and the physics Nobel Prizes many times even before the discovery of nuclear fission for their work on radioactive isotopes and protactinium. Several more nominations followed for the discovery of fission between 1940 and 1943. Nobel Prize nominations were vetted by committees of five, one for each award. Although both Hahn and Meitner received nominations for physics, radioactivity and radioactive elements had traditionally been seen as the domain of chemistry, and so the Nobel Committee for Chemistry evaluated the nominations in 1944.