Louis Renault built his first prototype in 1898. It had a 1.75 hp 273cc air-cooled De Dion-Bouton engine. Renault fitted it with a 3-speed gearbox that featured a patented direct top gear. The small company Louis Renault and his brothers Marcel and Fernand had established produced 60 cars in the first 6 months. Renault started manufacturing their own engines in 1902. Until about 1920 Renault concentrated on large, luxury cars. Smaller models appeared in 1923 to compete with Citroen. Renault was nationalised after the war. Post-war production started with an upgraded version of the Juvaquatre and the brand new 4CV, that had been developed in secret during the war. Over a million were made before production ceased in 1961.