The Nessonvaux factory began producing Imperia-Abadels from about 1916; in 1921, it built three ohc 5·6-liter straight-eights. These were quickly replaced by an ephemeral ohc 3-liter 32-valve four which was capable of going . This was followed by an 1100 cc side-valve 11/22 hp four designed by Couchard, one of the first cars ever built with a sunroof. Its engine rotated counter-clockwise, and its transmission brake also served as a servo for those on the front wheels. In 1937 a six of 1624 cc appeared; this had been available in three-carburettor Super Sports form from 1930. Over the course of four years Imperia took over three other Belgian car manufacturers: Métallurgique (1927), Excelsior (1929), and Nagant (1931). From 1934 until the company folded it built mainly front-wheel-drive Adlers with Belgian-made coachwork. The company merged with Minerva in 1934, but they split in 1939. After 1948 Impéria assembled Adlers and Standard Vanguards under license. After Standard decided to set up a new factory in Belgium, the factory was left without work and had to close doors in 1957.