A mitrailleuse (; from French "mitraille", "grapeshot") is a type of volley gun with barrels of rifle calibre that can fire either all rounds at once or in rapid succession. The earliest true mitrailleuse was invented in 1851 by Belgian Army captain Fafschamps, ten years before the advent of the Gatling gun. It was followed by the Belgian Montigny mitrailleuse in 1863. Then the French 25 barrel ""Canon à Balles"", better known as the Reffye "mitrailleuse", was adopted in great secrecy in 1866. It became the first rapid-firing weapon deployed as standard equipment by any army in a major conflict when it was used during the Franco-Prussian War of 1870–71.