The types of military forces in the Napoleonic Wars represented the unique tactical use of distinct military units, or their origin within different European regions. By and large the military forces during the period had not changed significantly from those of the 18th century, although their employment would differ significantly.
Military forces during the Napoleonic Wars consisted largely of the three principal combat arms, and several combat support services, and included the infantry, cavalry, artillery, engineers, and logistics troops which were called the army train during the period. The period gave a start to what are today military staffs to help administer and organise forces in the field and in garrisons, and supervise training of conscripts and recruits. Much of the staff work was performed by staff officers and often aide-de-camps to senior officers, and included the officers of the quartermaster general.
Napoleonic armies were formed from distinct infantry, cavalry, and artillery forces, each using distinctly different arms.
Infantry relied primarily on the musket, with the bayonet used for shock attack and defense from cavalry charges. Infantry could be described as line infantry, guards, grenadiers, light infantry or skirmishers, but the roles and arms employed often overlapped between these.
- Line infantry
- Infantry of the line were so named for the dominant line combat formation used to deliver a volume of musket fire. Forming the bulk of the Napoleonic armies it was the primary offensive and defensive Arm available to the commanders during the period. Movement in line formation was very slow, and unless the battalion was superbly trained, a breakdown in cohesion was virtually assured, especially in any kind of uneven or wooded terrain. As a result, when movement over such terrain was required over a significant distance troops would move in columns and then deploy into line at their destination.
- In addition, the line formation was vulnerable to cavalry charges, particularly from the flanks and rear, and these attacks usually resulted in the complete breakdown of cohesion and even destruction of the unit unless it was able to “form square“.
- The grenadierunits had, by the time of the Napoleonic Wars, ceased using the hand-thrown grenades, and were largely known for being composed of physically big men, frequently relied upon for shock actions. They otherwise used the same arms and tactics as other infantry.
- Light infantry
- The light infantry, variously known in different armies by different names, were first introduced into the regular armies during the wars of the 18th century as irregular troops, but became permanent parts of regular Napoleonic armies either as units in their own right, or as companies in the line infantry battalions. Perceiving themselves as superior troops due to being required to engage the enemy in small groups ahead of the other troops, requiring greater initiative and skill. Light infantry were also fully trained to fight in formation and so functioned as both line and light infantry when required.
- Many armies contained other light troops other than the officially designated ‘light infantry’. These units fought as dedicated skirmisher units ahead of the main force, such as the French Voltigeurs, German Jäger and British Rifles.