A cavalry is a military force mounted on horseback, according to Encyclopaedia Britannica. In previous centuries, a cavalry was an important element in the armies of all major powers. During the late 19th century, after the introduction of repeating rifles and machine guns, the cavalry lost most of its value.
As part of a military formation, the cavalry's main duties included observing and reporting information about the enemy, screening the movements of its own force and pursuing and demoralizing a defeated enemy. The cavalry's duties also included maintaining a constant threat to an enemy's rear area, striking suddenly at detected weak points, turning exposed flanks and exploiting a penetration or breakthrough. In the early 1960s, the U.S. 1st Cavalry Division was converted to an air mobile division with helicopters and air-portable weapons and vehicles.