<P> A rearguard is that part of a military force that protects it from attack from the rear, either during an advance or withdrawal . The term can also be used to describe forces protecting lines, such as communication lines, behind an army . Even more generally, a rearguard action may refer idiomatically to an attempt at preventing something though it is likely too late to be prevented; this idiomatic meaning may apply in either a military or non-military context . </P> <P> The term rearguard (also rereward, rearward) originates from the medieval custom of dividing an army into three battles or wards; Van, Main or Middle and Rear . The Rear Ward usually followed the other wards on the march and during a battle usually formed the rearmost of the three if deployed in column or the left - hand ward if deployed in line . </P> <P> The commonly accepted definition of a rearguard in military tactics was largely established in the battles of the late 19th century . Before the mechanization of troop formations, most rearguard tactics originally contemplated the use of cavalry forces . This definition was later extended to highly mobile infantry as well as mechanized or armored forces . </P> <P> Narrowly defined, a rearguard is a covering detachment that protects the retreating main ground force element (main body), or column, and is charged with executing defensive or retrograde movements between the main body and the enemy to prevent the latter from attacking or interfering with the movement of the main body . </P>

What do you call a rear guard footballer