Emile and Leon Nagant set up their manufacturing company in Liege, Belgium in 1859, and it would become one of the most prominent in the city. The brothers worked with a variety of other patent holders, including striking a deal with the Remington company. This would lead to Nagant production of rolling block rifles for the Vatican guards, and also the model 1877 Gendarmerie pistols.

Adopted as standard ams for the Belgian Gendarmerie and not replaced until the introduction of the Browning Model 1899, these were double-barreled rolling block action pistols chambered for the Belgian 9.4mm revolver cartridge. They have a single trigger and two hammers, and the trigger will fire either barrel if only one is cocked, or the right and then left barrel if both hammers are cocked (the trigger must be released to reset between barrels). A total of 2000 were made, and their Gendarmerie usage is indicated by the “W” stamp on the buttcap.