BMW AG (an acronym for Bayerische Motoren Werke Aktiengesellschaft, or in English, Bavarian Motor Works Corporation), is an independent German company and manufacturer of automobiles and motorcycles. BMW is the parent company of the MINI and Rolls-Royce car brands, and, formerly, Rover. BMW was founded by Karl Rapp, originally as an aircraft engine manufacturer, Bayerische Flugzeug-Werke. The Milbertshofen district of Munich was chosen, apparently because it was close to the Gustav Otto Flugmaschinenfabrik site. The blue-and-white roundel BMW still uses (illustrated above right) alludes to the blue and white checkered flag of Bavaria and also indicates the origin of BMW by symbolizing a spinning white propeller on a blue-sky background. In 1916 the company secured a contract to build V12 engines for Austro-Daimler. Needing extra financing, Rapp gained the support of Camillo Castiglioni and Max Friz, the company was reconstituted as the Bayerische Motoren Werke GmbH. Over-expansion caused difficulties; Rapp left and the company was taken over by the Austrian industrialist Franz Josef Popp in 1917, and named BMW AG in 1918.