In the 1920s, the cars used in endurance racing and Grand Prix were still basically identical, with fenders and two seats, to carry a mechanic if necessary or permitted. Cars such as the Bugatti Type 35 were almost equally at home in Grands Prix and endurance events, but specialisation gradually started to differentiate the sports-racer from the Grand Prix car. The legendary Alfa Romeo Tipo A Monoposto started the evolution of the true single-seater in the early 1930s; the Grand Prix racer and its miniature voiturette offspring rapidly evolved into high performance single seaters optimised for relatively short races, by dropping fenders and the second seat. During the later 1930s, French constructors, unable to keep up with the progress of the Mercedes-Benz and Auto-Union cars in GP racing, withdrew into primarily domestic competition with large-capacity sports cars - marques such as Delahaye, Talbot and the later Bugattis were locally prominent.
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