The vanguard (also called the advance guard) is the leading part of an advancing military formation. It has a number of functions, including seeking out the enemy and securing ground in advance of the main force.
The vanguard derives from the traditional division of a medieval army into three battles or wards; the Van, the Main (or Middle), and the Rear. The term Vanguard originates with the medieval French avant-garde, i.e. "the advance guard". The vanguard would lead the line of march and would deploy first on the field of battle, either in front of the other wards or to the right if they stood in line.
- a contingent of foreriders, from whom a forward detachment of scouts was drawn
- the main body of the vanguard, in which there traveled civil officials and trumpeters to carry messages and summon the surrender of towns and castles, and
- a body of workmen under the direction of the Master of Artillery whose job it was to clear obstacles which would obstruct the baggage and artillery travelling with the main army.
During World War 2, the Soviet-German War (1941-1945), beginning in July 1943, the Red Army began forming, as part of its offensive doctrine, ad hoc vanguard formations called forward detachments [peredovye otriady], from army, corps and divisional units. Forward detachments brought together the mobile (motorized or mechanized) elements of the parent formation to play an exploitation role once a breakthrough of the German lines occurred. A rifle division, for example, might mount one or two battalions of infantry on trucks, with motorized antitank guns and motorized artillery in support.
- Rogers, Clifford (2007). Soldiers Lives through History: The Middle Ages. Westport: Greenwood. p. 73. ISBN 978-0-313-33350-7.
- Michael, Nicholas (1983). Armies of Medieval Burgundy 1364–1477. London: Osprey. pp. 22–3. ISBN 0-85045-518-9.
- Rogers (2007), pp 76–7
- David M. Glantz, Colossus Reborn, University Press of Kansas, Lawrence, KS, 2005, pp. 110, 119