The 9×23mm Largo (9mm Largo, 9mm Bergmann-Bayard, 9mm Bayard Long) centerfire pistol cartridge was developed in 1901 for the Bergmann Mars pistol. The round was considered powerful for the day, producing a muzzle energy of between depending on the loading. A number of small changes to the Mars and the cartridge were made and the pistol that eventuated was called the Bergmann-Bayard 1903. At the same time the Bergmann-Bayard model 1910 semi-automatic pistol was adopted by the Danish military and remained in production until 1935.