The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines. Notable aircraft produced by the company include the 'Boxkite', the Bristol Fighter, the Bulldog, the Blenheim, the Beaufighter, and the Britannia, and much of the preliminary work which led to the Concorde was carried out by the company. In 1956 its major operations were split into Bristol Aircraft and Bristol Aero Engines. In 1959, Bristol Aircraft merged with several major British aircraft companies to form the British Aircraft Corporation (BAC) and Bristol Aero Engines merged with Armstrong Siddeley to form Bristol Siddeley.