Mounted unit of troops, specifically trained in the techniques of mounted warfare and deployed for their greater speed and manoeuvrability than infantry units. The term is still applied in modern warfare to refer to the mechanized units equipped with light tanks and armoured reconnaissance vehicles that have superseded traditional horse-mounted cavalry.
The development of reliable rifles and field artillery made cavalry more vulnerable in the 19th century, as was graphically demonstrated by the disastrous Charge of the Light Brigade during the Crimean War 1854. After tanks and armoured cars were developed in World War I, most armies abandoned their cavalry regiments in the interwar period.
Ancient world Horses have been used in battle since ancient times, at first mainly to draw chariots rather than for organized bodies of troops specifically trained in fighting on horseback. Other animals, including elephants, mules, and camels, have also been used. Although the Egyptians under Ramses II appear to have used some form of cavalry, it was not until horse-mounted troops were deployed by the Persians that the use of such troops became widespread in the ancient world. The Greeks did not generally use cavalry, relying instead on hoplite formations, but the Macedonians under Phillip II and Alexander the Great employed them to great effect. The Romans generally favoured fighting on foot, and depended mainly on allied ‘auxiliaries’ to supply their cavalry units, but many of their enemies had their own cavalry units.
Middle Ages Heavily armoured knights in chain mail were used as cavalry in Europe, while in Asia much of Genghis Khan's success in the 13th century may be attributed to his effective use of light cavalry units.
Modern Europe Cavalry tactics reached their height during the wars of the 18th and 19th centuries, with Napoleon putting mounted units to good use and the Cossack cavalry units playing a vital role in the Russian tsar's armies, both in war and in internal policing actions. By the late 19th century, cavalry units were proving increasingly vulnerable to automatic weapons and their effectiveness in battle diminished correspondingly. As the horse gave way to the car in civilian life, so cavalry lost ground to mechanized units in war. After the first tanks were deployed at the Battle of the Somme 1916, most armies replaced their cavalry units with mechanized troops in the 1920s and 1930s. Mounted troops today are largely retained for ceremonial roles, such as the British Blues and Royals regiment, who play an important and decorative role in escorting the monarch's carriage on state occasions.