MILITARY UNIT

Group of a prescribed size with a specific combat role within a larger military organization.

The chief units in the ancient world were the Greek phalanx and the Roman legion . Modern units originated in the 16th–18th century, when professional armies reemerged in Europe after the end of the Middle Ages. Since then the basic units

company, battalion , brigade , and division

have remained in use. The smallest unit today is the squad, which has 7–14 soldiers and is led by a sergeant. Three or four squads make up a platoon , and two or more platoons make up a company, which has 100–250 soldiers and is commanded by a captain or a major. Two or more companies make up a battalion, and several battalions form a brigade. Two or more brigades, along with various specialized battalions, make up a division, which has 7,000–22,000 troops and is commanded by a major general. Two to seven divisions make up an army corps, commanded by a lieutenant general, which with 50,000–300,000 troops is the largest regular army formation, though in wartime two or more corps may be combined to form a field army (commanded by a general), and field armies in turn may be combined to form an army group.