FUSILIER, originally (in French about 1670, in English about 1680) the name of a soldier armed with a light flintlock musket called the fusil; now a regimental designation. Various forms of flintlock small arms had been used in warfare since the middle of the 16th century. At the time of the English civil war (1642–1652) the term “firelock” was usually employed to distinguish these weapons from the more common matchlock musket. The special value of the firelock in armies of the 17th century lay in the fact that the artillery of the time used open powder barrels for the service of the guns, making it unsafe to allow lighted matches in the muskets of the escort. Further, a military escort was required, not only for the protection, but also for the surveillance of the artillerymen of those days. Companies of “firelocks” were therefore organized for these duties, and out of these companies grew the “fusiliers” who were employed in the same way in the wars of Louis XIV. In the latter part of the Thirty Years’ War (1643) fusiliers were simply mounted troops armed with the fusil, as carabiniers were with the carbine. But the escort companies of artillery came to be known by the name shortly afterwards, and the regiment of French Royal Fusiliers, organized in 1671 by Vauban, was considered the model for Europe. The general adoption of the flintlock musket and the suppression of the pike in the armies of Europe put an end to the original special duties of fusiliers, and they were subsequently employed to a large extent in light infantry work, perhaps on account of the greater individual aptitude for detached duties naturally shown by soldiers who had never been restricted to a fixed and unchangeable place in the line of battle. The senior fusilier regiment in the British service, the (7th) Royal Fusiliers (City of London Regiment), was formed on the French model in 1685; the 5th foot (now Northumberland Fusiliers), senior to the 7th in the army, was not at that time a fusilier regiment. The distinctive head-dress of fusiliers in the British service is a fur cap, generally resembling, but smaller than and different in details from, that of the Foot Guards.

In Germany the name “fusilier” is borne by certain infantry regiments and by one battalion in each grenadier regiment.