An army officer, he founded the fascist Nasjonal Samling (National Unity) Party, and in 1940 helped Hitler to prepare the conquest of Norway. He became head of a new pro-German government and was made Premier in 1942. He remained in power until 1945, when he was arrested and executed. By this time ‘Quisling’ had become a derogatory term to describe traitors who supported invaders of their countries.