Heavy cavalry were armoured riders on large, strong horses, built to deliver a shock charge that broke enemy formations. Light cavalry were lightly equipped riders on fast, hardy horses whose job was scouting, screening, skirmishing, raiding and pursuing a beaten enemy. Armies needed both: the heavy horse won the decisive moment, the light horse made sure there was a decisive moment to win.
For more than two thousand years generals sorted their horsemen into two broad families. One was a battering ram: men in armour on the biggest horses money could buy, kept in reserve for the blow that would break a line. The other was the army's eyes and claws: faster, cheaper riders who found the enemy, hid their own side's movements, harassed, raided and chased.
The labels changed with every era, from cataphracts and knights to cuirassiers and hussars, and some units drifted from one family to the other. But the basic trade-off never did: protection and mass against speed and endurance.
What is heavy cavalry?
Heavy cavalry is defined by its purpose: the charge. Its riders wore the best armour of their day and rode large horses bred for strength, so that a tight formation could hit an enemy line with enough weight and terror to break it. Alexander's Companions, the armoured cataphracts of Parthia and Byzantium, the medieval knight, the winged hussar and the Napoleonic cuirassier all belong to this family.
That power came at a price. Heavy horsemen and their mounts were expensive to raise and feed, tired quickly, and were wasted if thrown at the wrong target. Steady infantry with long spears or, later, with muskets in a square could stop them cold, which is why commanders kept them in reserve for the moment an enemy began to waver.
What is light cavalry for?
Light cavalry did almost everything else. It scouted ahead to find the enemy and screened its own army from enemy scouts. It raided supply lines, cut off foragers, harassed columns on the march and, above all, pursued a beaten army so that a defeat became a rout. Light horsemen carried little or no armour and often fought at a distance with bows, javelins or later carbines, closing with the sabre only when the odds were good.
The steppe peoples raised light cavalry to its peak. Mongol warriors were mostly horse archers who rode with several remounts each1, which let them cover distances no other army could match. Cossacks, Tatars, Hungarian hussars and later the light regiments of Napoleon's army inherited the same roles: speed, reach and endurance rather than weight.
How the two worked together
The best armies combined both. At Cannae in 216 BC Hannibal's heavy Spanish and Gallic cavalry broke the Roman horse2 on one wing, while his Numidian light horsemen pinned the allied cavalry2 on the other until the heavy squadrons came round to finish them. Together they closed the ring around the legions.
The Mongols worked the same partnership inside a single army. Horse archers wore the enemy down with arrows and feigned retreats, and once the enemy was disordered, more heavily armed lancers delivered the final charge1. Medieval European knights, by contrast, often had too little light cavalry of their own, and against Turkish and Mongol horse archers they could be shot at for hours without ever reaching their tormentors.
Knights against horse archers
The Crusades show the same contest from the other side. At Arsuf in 1191 Richard the Lionheart marched his army along the coast while Saladin's mounted archers harassed it for hours. Richard held his knights back as long as he could, and when the charge finally went in, started a little early by the Hospitallers, it drove Saladin's army from the field. Patience turned heavy cavalry from a target into a hammer.
Four years earlier at Hattin the opposite happened: a crusader army without water, worn down on the march, could never land a decisive charge, and was destroyed. The lesson ran through every era: heavy cavalry needed the right moment, and light cavalry existed to deny it that moment.
Hussars: when the names get confusing
The word hussar shows how loose the labels became. Hussars began in Hungary and the Balkans as light raiding horsemen3. In Poland and Lithuania, however, the hussar evolved during the sixteenth century into an armoured heavy lancer3, the famous winged hussar, whose charges broke far larger armies at Kircholm in 1605 and Klushino in 1610.
Meanwhile the rest of Europe copied the Hungarian original, and by the eighteenth century hussars in the Austrian, Prussian and French armies were light cavalry in braided jackets. Dragoons followed the opposite path: they started as mounted infantry who rode to battle and fought on foot, and gradually became ordinary line cavalry, a middle weight between the cuirassiers and the light regiments.
Balaclava, 1854: both brigades on the same day
No battle shows the difference more clearly than Balaclava on 25 October 1854. In the morning the Heavy Brigade under James Scarlett, about 800 horsemen, charged uphill into some 3,000 Russian cavalry4 and threw them into disorder. Weight, close order and discipline did exactly what heavy cavalry was meant to do.
A few hours later, after a misunderstood order, the Light Brigade, 673 strong4, rode down a valley into the wrong Russian guns, under fire from three sides. Around 260 men were killed or wounded and 475 horses4 were lost. Light cavalry used as shock troops against artillery was simply destroyed.
How firearms changed the balance
Gunpowder did not kill cavalry at once. Through the seventeenth and eighteenth centuries horsemen adapted with pistols, carbines and the charge with the sword. Napoleon still kept great masses of heavy cavalry, but at Waterloo Marshal Ney's repeated charges broke against Allied squares5, because without infantry and artillery support even the best cuirassiers could not crack steady musketry.
Rifles, machine guns and quick-firing artillery finished the job. At Mars-la-Tour in 1870 the last major cavalry engagement in western Europe was fought6, at heavy cost. Armour became useless against rifle bullets, so the old distinction faded: in the twentieth century almost all cavalry was in effect light or mounted infantry, riding to battle and fighting dismounted, as Polish cavalry did7 at Mokra in 1939 against German armour. The role of heavy shock passed to the tank, and that of light reconnaissance to armoured cars and, eventually, aircraft.
