Edouard Koehn or Ed. Koehn (1839-1908) started his horological career in the workshops of Patek Philippe as a watchmaker. In 1891 Koehn took over H.R. Ekegren, keeping the company's name and the founder as chief engineer until the latter's death in 1896. The firm, as of 1908 managed by Koehn's son Edouard, specialized in the production of flat or extra flat watches and complications and the improvement of the retrograde display mechanism. It appears that the company was dissolved in the mid 1930s.