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Light cavalry comprised lightly armed and armored cavalry troops mounted on fast horses, as opposed to heavy cavalry, where the mounted riders (and sometimes the warhorses) were heavily armored. The purpose of light cavalry was primarily raiding, reconnaissance, screening, skirmishing, patrolling and tactical communications. Prior to the early 17th century they were usually armed with swords, spears, javelins, or bows, and later on with sabres, pistols, shotguns, or carbines.
Light cavalry was used infrequently by Ancient Greeks (who used hippeis such as prodromoi or sarissophoroi) and Ancient Romans (who used auxiliaries such as equites Numidarum or equites Maurorum), but were more common among the armies of Eastern Europe, North Africa, West Asia, Central Asia and East Asia. The Arabs, Cossacks, Hungarians, Huns, Kalmycks, Mongols, Turks, Parthians, and Persians were all adept light cavalrymen and horse archers.
With the decline of feudalism and knighthood in Europe, light cavalry became more prominent in the armies of the continent. Many were equipped with early firearms, as their predecessors had been with bows or javelins. European examples of light cavalry included stradiots, hobelars, hussars, chasseurs à cheval , cossacks, chevau-légers , uhlans, and some dragoons. 
Armies of the ancient Roman-Germanic wars made use of light cavalry as patrolling squads, or armed scouts, and often had them in the front lines during regional battles.
During the Punic Wars, one of Carthage's main advantages over Roman armies was its extensive use of Numidian light cavalry. Partly because of this, the Roman general Scipio Africanus recruited his own cavalry from Sicily before his invasion of Tunisia during the Second Punic War.
Types of light cavalry that were developed and used in medieval armies.
Light cavalry played a key role in mounted scouting, escorting, and skirmishing during the Napoleonic era. Light horse also served a function in major set-piece battles. While lacking the sheer offensive power of heavy cavalry, light cavalry were still extremely effective against unprepared infantry, cavalry, and artillery. All infantry commanders were forced to respect the danger any cavalry presented to their forces, and light cavalry were effective at changing the movement of enemy forces simply through their presence. In the aftermath of battles, light cavalry were used to press a victor's advantage or to screen retreating forces from further attack.
As late as the early 1900s, most European armies still retained a nominal division of mounted troops according to the size and weight of the men,  into light cavalry (raiding, reconnaissance, and screening), medium cavalry (offense or defense), and heavy cavalry (direct shock).  While colonial warfare had led to a blurring of these distinctions in the British army, tradition remained strong in the cavalry arm of some other nations. As an example, the Imperial German army maintained a marked difference between the sizes and weights of the men and horses allocated to the hussar regiments that made up its light cavalry and those of the other two categories.  The early weeks of World War I saw light cavalry attempting to continue its long established function of being the "eyes and ears" of the respective main armies. However, despite some early success, the advent of trench warfare and aircraft observation quickly rendered this role obsolete, except to an extent in the Middle East in 1917, and in Eastern Europe where light cavalry mounted actions on a diminishing scale continued to occur until the revolution of 1917 took Russia out of the war. 
During the Vietnam War, the US Army converted parts of the 1st Cavalry Division for heliborne tactics with a concept known as Air Cavalry. Helicopters were used to insert troops and support them. They were also used for suppression fire, search and rescue, medical evacuation, scouting and resupply. This concept was first tested at the Battle of Ia Drang Valley.   Modern tactics call for the use of gunships to dominate the airspace and provide fire support while transport helicopters ferry ground forces and supply them.
Light reconnaissance vehicles (LRV) are also being used by cavalry squadrons and infantry scout units for scouting, skirmishing and providing light fire support. 
Historically, cavalry are soldiers or warriors who fight mounted on horseback. Cavalry were the most mobile of the combat arms, operating as light cavalry in the roles of reconnaissance, screening, and skirmishing in many armies, or as heavy cavalry for decisive shock attacks in other armies. An individual soldier in the cavalry is known by a number of designations depending on era and tactics, such as cavalryman, horseman, trooper, cataphract, knight, drabant, hussar, uhlan, mamluk, cuirassier, lancer, dragoon, or horse archer. The designation of cavalry was not usually given to any military forces that used other animals for mounts, such as camels or elephants. Infantry who moved on horseback, but dismounted to fight on foot, were known in the early 17th to the early 18th century as dragoons, a class of mounted infantry which in most armies later evolved into standard cavalry while retaining their historic designation.
Dragoons were originally a class of mounted infantry, who used horses for mobility, but dismounted to fight on foot. From the early 17th century onward, dragoons were increasingly also employed as conventional cavalry and trained for combat with swords and firearms from horseback. While their use goes back to the late 16th century, dragoon regiments were established in most European armies during the 17th and early 18th centuries; they provided greater mobility than regular infantry but were far less expensive than cavalry.
A lance is a spear designed to be used by a mounted warrior or cavalry soldier (lancer). In ancient and medieval warfare, it evolved into the leading weapon in cavalry charges, and was unsuited for throwing or for repeated thrusting, unlike similar weapons of the javelin and pike family typically used by infantry. Lances were often equipped with a vamplate, a small circular plate to prevent the hand sliding up the shaft upon impact, and beginning in the late 14th century were used in conjunction with a lance rest attached to the breastplate. Though best known as a military and sporting weapon carried by European knights and men-at-arms, the use of lances was widespread throughout Asia, the Middle East, and North Africa wherever suitable mounts were available. Lancers of the medieval period also carried secondary weapons such as swords, battle axes, war hammers, maces and daggers for use in hand-to-hand combat, since the lance was often a one-use-per-engagement weapon; assuming the lance survived the initial impact without breaking, it was often too long, heavy, and slow to be effective against opponents in a melee.
A hussar was a member of a class of light cavalry, originating in Central Europe during the 15th and 16th centuries. The title and distinctive dress of these horsemen were subsequently widely adopted by light cavalry regiments in European armies during the late 17th and 18th centuries. By the 19th century, hussars were wearing jackets decorated with braid plus shako or busby hats and had developed a romanticized image of being dashing and adventurous.
The Polish cavalry can trace its origins back to the days of medieval cavalry knights. Poland is mostly a country of flatlands and fields and mounted forces operate well in this environment. The knights and heavy cavalry gradually evolved into many different types of specialised mounted military formations, some of which heavily influenced western warfare and military science. This article details the evolution of Polish cavalry tactics, traditions and arms from the times of mounted knights and heavy winged hussars, through the times of light uhlans to mounted infantry equipped with ranged and mêlée weapons.
Cuirassiers were cavalry equipped with a cuirass, sword, and pistols. Cuirassiers first appeared in mid-to-late 16th century Europe as a result of armoured cavalry, such as men-at-arms and demi-lancers, discarding their lances and adopting the use of pistols as their primary weapon. In the later part of the 17th century the cuirassier lost his limb armour and subsequently wore only the cuirass, and sometimes a helmet. By this time, the sword or sabre had become his primary weapon, with pistols relegated to a secondary function.
The Battle of Kircholm was one of the major battles in the Polish–Swedish War (1600–1611). The battle was decided in 20 minutes by the devastating charge of Polish-Lithuanian cavalry, the Winged Hussars. The battle ended in the decisive victory of the Polish-Lithuanian forces, and is remembered as one of the greatest triumphs of Commonwealth cavalry.
Skirmishers are light infantry or light cavalry soldiers deployed as a vanguard, flank guard or rearguard to screen a tactical position or a larger body of friendly troops from enemy advances. They are usually deployed in a skirmish line, an irregular open formation that is much more spread out in depth and in breadth than a traditional line formation. Their purpose is to harass the enemy by engaging them in only light or sporadic combat to delay their movement, disrupt their attack, or weaken their morale. Such tactics are collectively called skirmishing.
A lancer was a type of cavalryman who fought with a lance. Lances were used for mounted warfare in Assyria as early as 700 BC and subsequently by Persia, India, Egypt, China, Greece, and Rome. The weapon was widely used throughout Eurasia during the Middle Ages and the Renaissance by heavy cavalry, but fell out of general use in the late 16th century before its revival by light cavalry in the 19th century.
Mounted infantry were infantry who rode horses instead of marching. The original dragoons were essentially mounted infantry. According to the 1911 Encyclopædia Britannica, "Mounted rifles are half cavalry, mounted infantry merely specially mobile infantry." Today, with motor vehicles having replaced horses for military transport, the motorized infantry are in some respects successors to mounted infantry.
The Coalition forces of the Napoleonic Wars were composed of Napoleon Bonaparte's enemies: the United Kingdom, the Austrian Empire, Kingdom of Prussia, Kingdom of Spain, Kingdom of Naples, Kingdom of Sicily, Kingdom of Sardinia, Dutch Republic, Russian Empire, the Ottoman Empire, Kingdom of Portugal, Kingdom of Sweden, and various German and Italian states at differing times in the wars. At their height, the Coalition could field formidable combined forces of about 1,740,000 strong. This outnumbered the 1.1 million French soldiers. The breakdown of the more active armies are: Austria, 570,000; Britain, 250,000; Prussia, 300,000; and Russia, 600,000.
Heavy cavalry was a class of cavalry intended to deliver a battlefield charge and also to act as a tactical reserve; they are also often termed shock cavalry. Although their equipment differed greatly depending on the region and historical period, heavy cavalry were generally mounted on large powerful warhorses, wore body armor, and armed with either lances, swords, maces, flails (disputed), battle axes, or war hammers; their mounts may also have been protected by barding. They were distinct from light cavalry, who were intended for scouting, screening, and skirmishing.
For much of history, humans have used some form of cavalry for war and, as a result, cavalry tactics have evolved over time. Tactically, the main advantages of cavalry over infantry troops were greater mobility, a larger impact, and a higher position.
Armoured cavalry are combat units using armoured fighting vehicles (AFVs) instead of horses. They began to replace horse cavalry in the heavy shock and the light reconnaissance, skirmishing and exploitation/pursuit roles in most armies commencing after the First World War.
There are 13 Cavalry Regiments of the British Army each with its own unique cap badge, regimental traditions, and history. Of the currently nine regular cavalry regiments, two serve as armoured regiments, three as armoured cavalry regiments, three as light cavalry, and one as a mounted ceremonial regiment. There are also four yeomanry regiments of the Army Reserve, of these, three serve as light cavalry and one as an armoured regiment. Each yeomanry light cavalry unit has been paired with a regular unit of the same role, the armoured yeomanry unit is paired with the two regular armoured units. All except the Household Cavalry are part of the British Army's Royal Armoured Corps.
The types of military forces in the Napoleonic Wars represented the unique tactical use of distinct military units, or their origin within different European regions. By and large the military forces during the period had not changed significantly from those of the 18th century, although their employment would differ significantly.
A pistoleer is a mounted soldier trained to use a pistol, or more generally anyone armed with such a weapon. It is derived from pistolier, a French word for an expert marksman.
Petyhorcy was a type of regular medium-armoured light cavalry exclusively in the Grand Ducal Lithuanian Army during the 17th and 18th centuries. The petyhorcy are viewed as the Lithuanian equivalent of the Royal Polish Army's Armoured Companion, or as a cavalry type that was between the Winged Hussars and the Armoured Companion. They were organised in Banners. Originally, the Petyhorcy were spear-armed cavalry from Circassia.
The military forces of the Afsharid dynasty of Iran had their origins in the relatively obscure yet bloody inter-factional violence in Khorasan during the collapse of the Safavid state. The small band of warriors under local warlord Nader Qoli of the Turkoman Afshar tribe in north-east Iran were no more than a few hundred men. Yet at the height of Nader's power as the king of kings, Shahanshah, he commanded an army of 375,000 fighting men which, according to Axworthy, constituted the single most powerful military force of its time, led by one of the most talented and successful military leaders of history.
"New order regiments"(Russian: "Полки иноземного строя"), also known in the literature as "foreign formation regiments", were professional military units formed in Russian Tsardom in the 17th century, armed and trained in line with the Western European armies.