A regiment is a military unit, composed of a variable number of battalions – commanded by a Colonel. Depending on the nation, military branch, mission, and organization, a modern regiment resembles a brigade, in that both range in size from a few hundred to 5,000 soldiers (3 to 7 standard battalions). Generally, regiments and brigades are grouped as divisions. The modern regiment's size varies in number, scope, and administrative role from country to country (and might not exist in some military forces) and sometimes even within the military of the same nations.

Historical origin

The French term régiment entered military usage in Europe at the end of the 16th century, when armies evolved from collections of retinues who followed knights, to a formally organised, permanent military force. At that time, regiments usually were named after their commanding colonels, and disbanded at the end of the campaign or war. At that time, the colonel and his regiment might recruit from and serve several masters (countries). Later, it was customary to name the regiment by its geographic precedence in the line of battle, and to recruit from specific places, the cantons. The oldest, existent regiment is the Swedish Life Guards, although the French claim that their 1st Infantry Regiment is the eldest, being created in 1479 from the ancient "Bandes de Picardies".

In the 17th century brigades were formed as combined arms units (infantry, cavalry, artillery) that were more effective than the older, single-arms regiments; in many armies, brigades replaced regiments.

Regimental system

The regimental army organisation system often is contrasted to the "continental system" (adopted by European armies). In the continental system, the division is the functional army unit, and its commander the administrator of every aspect of the formation: his staff train and administer the soldiers, officers, and commanders of the division's subordinate units. Generally, divisions are garrisoned together and share the same installations, thus, in divisional administration, a battalion commanding officer is just another officer in a chain of command; soldiers and officers are transferred in and out of divisions as required.

In the regimental system, each regiment is responsible for recruiting, training, and administration; each regiment is permanently maintained, therefore, the regiment will develop its unique esprit de corps because of its unitary history, traditions, recruitment, and function. Usually, the regiment is responsible for recruiting and administrating a soldier's military career. Depending upon the country, regiments can be either combat units or administrative units or both.