The late Roman Empire saw a transition away from the infantry legions which had built it toward cavalry, necessary to defend it against the horse soldiers of invading barbarian tribes. During the second millennium C.E., the Fulbe of West Africa built an empire from horseback, as did the feudal knights of Songhay. In fact, cavalry empires dominated West Africa until they met their match in the infantry of the Ashante and other coastal and forest peoples, newly armed with European firearms. The Bedouin empire was won by Arabian cavalry, while the Mongols conquered the greatest land empire in history from the backs of fleet war ponies, and with composite bows and incomparable ruthlessness. The Mamlu-ks of Egypt were a cavalry dynasty that held the reins of overlordship in much of the eastern Mediterranean for nearly 800 years. They survived in truncated form nearly to the 19th century, until crushed by Napoleon at the ”Battle of the Pyramids” in 1798. Ottoman armies were dominated by akinci freelance cavalry, heavy mailed sipahis, light cavalry timariots, and allied Tatar scouts and skirmishers. Even at the peak of Janissary enlistment Ottoman armies never exceeded one infantryman for every two horse soldiers. The armies of the Safavids of Iran were almost exclusively cavalry until the time of Abbas I. Then the Safavids shifted from cavalry as their principal arm, not least because they lost too often and badly to Ottoman gun-bearing infantry and mobile artillery. Horse cavalry did not dominate Indian warfare primarily because the humid Indian climate was inimical to most breeds. Instead, Indian armies relied on elephants as cavalry, military transports, and in construction of fortifications.

Whatever the breed of warhorse, and despite sharp limitations imposed on horse archers by siege warfare, only cavalry could effectively patrol borders, provide swift reinforcement of threatened areas, and hound and pursue a defeated enemy. Medieval Europe was constructed socially as well as militarily around the mounted warrior, as much or more than it was based on the Church. In England, medieval cavalrymen were divided into bannerets, knights, and men-at-arms. In France the key distinction was between those knights who were ”dubbed,” and those who were not (sergeants or squires) Knights became progressively more heavily armored in response to the penetrating power of the crossbow and of early gunpowder weapons. They were the core of all Crusader armies and frequently won against staggeringly greater numbers of Muslim infantry and light horse. Their dominance of the battlefield in Europe began to erode from the late 13th century when England’s heavy cavalry was surprised and defeated by William Wallace’s army of fierce Scots at Stirling Bridge (1297).

More influentially, Flemish militia decimated the French mounted nobility at Courtrai (1302). Learning from this, Robert I (”The Bruce”) defeated the English again at Bannockburn (1314). In all these fights, heavily armored men on big horses, of the type that dominated Norman and European warfare for 200 years, were met and bested by common infantry. To even greater educational and psychological effect, Swiss infantry formed into pike squares began to inflict ever greater defeats on Austrian knighthood, at Morgarten (1315), Laupen (1339), Sempach (1386), and Na¨fels (1388). Once they had fully incorporated the pike into their tactics, after a close battle at Arbedo (1422), they destroyed the Burgundian heavy horse at Grandson (1476), Morat (1476), and Nancy (1477).

Within Europe, the distinction of cavalry from infantry was military and social: the French ”chevalier” (”horse warrior”) or Italian warrior from one of the consorterie came from the aristocracy. He was distinguished from a peasant or town militiaman by his warhorse, armor, and weapons, especially the couched lance and sword. Such a heavy cavalryman was recruited from between 2 and 4 percent of the population, at most. Only in France, therefore, did large population and national wealth mean that armies were made up principally of aristocrats. Elsewhere, infantry from the lower orders necessarily supplemented small feudal levies. In chivalric warfare most horse actions involved a line of armored horsemen (1,500 to 2,000 three or four ranks deep formed a line one mile wide) charging en masse to achieve maximum shock effect. Opposing infantry either opened alleys before the great, panting and pounding destriers, or broke apart and scattered. In either case, armored nobles happily slaughtered with lance and sword the unarmored peasants or town militia as they ran in terror.

However, infantry tactics evolved around various forms of the pike that effectively countered cavalry shock. When first faced with disciplined arrays of infantry with long spears, and still brimming with an arrogant sense of class and martial superiority, noble cavalry rode on in the same old way to meet disaster at Courtrai, Bannockburn, and elsewhere. Of course, adaptation came with time. The first, simple expedient was a new role assigned to specialized infantry. As enemy archers did their best to interrupt one’s heavy cavalry charge with harassing fire into the assembling mass of lumbering horsemen, it became the crucial job of friendly pike infantry to protect friendly archers deployed to pin down the enemy archers interfering with the charge. A sort of light artillery duel ensued, with archers fighting archers. While this occurred, the heavy cavalry could form and move, accelerating into a full charge against the enemy line of infantry or horse at the critical moment (from about 50 to 100 meters out).

Where such counter-archery preliminary to the charge was not employed, where the cavalry instead charged first and unsupported by infantry archers as the French did at Courtrai, the result was massive defeat and heavy casualties among the noble horse. Cavalry slowly learned to avoid the head-on charge in favor of sweeping wide to encircle the infantry’s flanks, or to maneuver to the rear to attack the baggage train. However, the main shift in horse soldier tactics-starting in England in the early 1330s-was for cavalry to dismount so that men-at-arms could fight on foot, using their lances as pikes before turning to the sword and mace for close-in fighting. Such tactics still permitted dismounted men to resume a cavalry role for pursuit of a fleeing enemy once close fighting and archery had broken his line. In this the English nobility had learned much from their earlier defeats by pikemen in the Scottish Wars, when they were led by Edward I and his son, Edward II. Under the grandson, Edward III, radical new tactics were used to defeat a far larger Scots army at Halidon Hill (1333).

The new English tactics called for longbowmen protected by shaved stakes or stands of pikemen to stand forward of the flanks of the main body of English men-at-arms, who dismounted to hold the center of the English line. Or, longbow formations were placed at the flanks of each of two or three smaller ranks of dismounted knights. The archers then shot out arrow storms at long range, breaking up the enemy formations or provoking them to premature attack, which was met well by the dismounted men-at-arms. In this way, Edward destroyed the Scots national host. These new tactics were taken to France by Edward III and his son, the Black Prince, and by their successors during the Hundred Years’ War (1337-1453). The heavy cavalry of the French nobility first ran into them at Cre´cy (1346). The scale of that defeat taught the French nobility to also dismount so that they, too, fought on foot at Poitiers (1356) and later. Lessons learned are often forgotten, however, so that decades later Henry V again used Edward III’s formations and tactics to kill and capture thousands of mounted French knights at Agincourt (1415). The gunpowder revolution greatly increased infantry firepower at the expense of cavalry, while siege warfare hampered cavalry’s effectiveness.

The advent of effective firearms in time unhorsed the knight by rendering his own armor and that of his mount equally useless. In Western Europe, 14th- and 15th-century cavalry tried to counter with their own firearms by adopting the pistol and developing the caracole. But this proved of little effect against pike squares and musketeers, who drove cavalry to the margins of the battlefield. During the early years of the Thirty Years’ War, cavalry made up about 20-25 percent of most armies. Heavy cavalry was often supplemented with ”dragoons,” musket-bearing mounted infantry, who provided mobile firepower. Light cavalry provided reconnaissance and skirmishers to the large infantry armies that dominated the early 17th century.

The great innovator was Gustavus Adolphus, who modeled his cavalry reforms on the Polish style, reducing armor in favor of leather (buff coats) or plain uniforms, and replacing the ineffective pistol and caracole cantor with the slashing saber and fullspeed charge. This change was captured in the fierce and merciless battle cry of his feared Finnish horse: ”hakkaa paalle!” (”cut them down”). Sweden’s success provoked imitators throughout Germany and as far afield as England, where at mid-century Cromwell and the cavalry of the New Model Army adopted the proven Swedish tactics and training and drove the individually more skilled horsemen of the Cavaliers from the field. On the continent, the ratio of cavalry to infantry increased dramatically after 1635, to 50 percent or more. This was largely due to logistical problems: horsemen could forage more widely, which was necessary in lands burned and eaten out over several decades of war.

In Eastern Europe, things were very different. Light cavalry hussars and medium cavalry of the Polish Army dominated, fighting against vast horse armies of Tatars and Cossacks, as well as against Swedish horse and Russian servitor cavalry. The most probable explanation of this significant difference was topography rather than ”inferior” or ”backward” military culture, as too many Western European histories have suggested. The need for infantry in chronic warfare with mounted nomads, other than in garrisons armed with firearms, was minimal. Instead, eastern armies properly recognized that foot soldiers, other than dragoons, could not yet make up in firepower on the vast eastern plains what they lacked in mobility, even when protected by pikes. And since infantry was mostly ineffective in Eastern Europe and on the Ukrainian and Russian steppes, cavalry remained the principal arm. Likewise, light cavalry could not operate as well as infantry in the densely populated, heavily forested, and riverine geography of Western Europe (or the mountains of Japan), so that infantry over time became the preferred arm in those areas, with archers and gunmen protected by pikemen or ashigaru.