D. Napier & Son Limited was a British engine and pre-Great War (the 'brass era') automobile manufacturer and one of the most important aircraft engine manufacturers in the early- to mid-20th Century. Their post-World War I Napier Lion was the most powerful engine in the world for some time in the 1920s and into the 1930s, and their Napier Sabre engine produced 3500 hp (2,600 kW) in its later versions.