the Austrian financier Camillo Castiglioni. In this way, he was able to break free from Knorr-Bremse AG and start up engine construction once more. New areas of business The rise of BMW to one of Bavaria’s and Germany’s big industrial companies began in 1922 under Popp’s management. The product range of BMW AG was expanded and soon it extended beyond engines for the aircraft industry to include motorcycles as broader sections of the population gained access to motorized transport. This was an area to which Popp devoted considerable attention. Under his chairmanship, BMW AG further expanded its product range and know-how in 1928 by purchasing the vehicle manufacturing factory Fahrzeugfabrik Eisenach (FFE). This was the first time that cars bore the BMW brand on the roads. In 1928, Popp also concluded a license agreement with the US American company Pratt & Whitney, allowing BMW to manufacture two air-cooled radial engines. This ensured that BMW had access to key know-how in an area of aircraft engine construction with a great future. The expertise acquired through production under license allowed BMW to develop air-cooled radial engines under its own steam during the 1930s. Construction of the BMW aircraft engine factory in Allach (1935), expansion of the manufacturing facilities in Eisenach (1937) and acquisition of the Brandenburg Motor Works (Bramo) in Berlin-Spandau enabled BMW to expand capacities for aircraft engine manufacture under Popp’s leadership. Following the acquisition of Bramo in 1939, BMW enjoyed a monopoly for the production of air-cooled aircraft engines in Germany. This made BMW a key strategic company for the German aviation industry as the Third Reich rearmed. However, Popp was skeptical of the rapid expansion and redirection of the company for purposes of arming Germany in preparation for war. Political meddling These reservations were not politically motivated. Even though Popp admitted that he joined the Nazi Party on 1 May 1933 under pressure from Gauleiter Wagner, head of the Bavarian administrative district, he kept his distance from the party. Looking back, he maintained that joining the party shortly after the National Socialists seized power was simply intended to prevent his removal as General Director of BMW. In February 1936, the local group leader of the National Socialist Party started proceedings to exclude Popp from the party. This was based on accusations that despite warnings, Popp continued to allow his family to be treated by a Jewish family doctor. Following