Chapter 3 - The Military Revolution
The armies of the Iron Age also made revolutionary advances in tactical mobility and proficiency that had important effects on the conduct of war. Tactical mobility can be defined as the ability of small combat units to perform sophisticated tactical maneuvers in order to increase the combat power of these units, thereby increasing the overall combat effectiveness of the army as a whole. The increase in tactical flexibility of small units in ancient armies resulted from a number of factors. While each one taken alone had only a small effect on unit combat power, when the factors were taken together the overall impact was truly significant.
The Assyrian invention of the leather jackboot provides an excellent example. Earlier armies of the Middle East wore the open sandal as regular military footwear. While sufficient in sandy desert climates, sandals were ineffective in preventing foot injuries to troops forced to conduct operations in rough terrain. Moreover, sandals offered no protection for soldiers who served in armies that had large horse contingents. The press of an animal's hoof upon a soldier's foot could cause frequent and debilitating injuries. Sandals provided little protection to the soldier who fought within a packed infantry phalanx and offered a severe disadvantage to soldiers fighting in cold climates. The lack of adequate footgear was a major factor in limiting the tactical mobility of the early ancient armies.
The Assyrian army was the first to improve on the military footwear of ancient armies. The Assyrian soldier wore a knee-high, leather jackboot with thick leather soles complete with hobbed nails to improve traction. The boot also had thin plates of iron sewn into the front to provided for protection for the shin. The high boot provided effective ankle support for troops who fought regularly in rough terrain and served as excellent protection in cold weather, rain, and snow. The boot kept foot injuries to a minimum and was one of the primary reasons why the Assyrian army was able to move easily over rough terrain in all kinds of weather. Following the Assyrian lead, military boots of various designs became standard equipment for all the later armies of the Iron Age.
The growth in tactical flexibility of small units was also evident in the ability of armies to develop an all-weather capability for ground combat. The Assyrians regularly fought in the summer and winter months, and even carried out siege operations in the winter. Sargon II's campaign against the Urartu (Armenia) in 714 B.C. provided a textbook example of the development of improved tactical proficiency. The campaign was conducted almost 600 miles from the Assyrian capital in the late fall. Sargon's army, complete with contingents of infantry, cavalry, and heavy chariots, traversed mountains, streams, and rivers on the route of march. Travel through the mountain passes was complicated by heavy snows. One pass was so high and heavily blocked by snow that the enemy did not bother to defend it. Sargon negotiated the pass, caught the enemy by surprise, fought and won a major battle, and still had enough combat power left to besiege and capture a fortified city.
The Assyrians also fought well in marshlands. Placed aboard light reed boats, tactical combat units became waterborne marines who used fire arrows and torches to burn out the enemy hiding among the bushes and reeds of the swamp. The ability to mount military operations in all kinds of weather and terrain became a vital military capability for all later Iron Age armies. Alexander, Hannibal, and the Roman legions all developed the capacity to fight regularly in rough terrain and harsh weather.
The regular use of tactical engineering units provided yet another increase in the combat power of field units. Assyrian engineers mastered the technique of building the world's first military pontoon bridges from palm wood planks and reeds. At times they used inflatable animal skin bags for flotation devices for both men and animals. The large cavalry contingents of the Persian army required that their combat engineers become skilled at the rapid construction of bridges with vertical sides so that the horses could cross steep ravines without fear driving them to bolt. Persian engineers were capable of diverting the course of a river to deprive an enemy fleet of its water, a trick they performed in the war against Egypt. In the Babylonian War, military engineers diverted the course of a stream running through the city so that infantry could enter under the walls by moving along the dry stream bed. Military engineering, of course, reached its height in the ancient world among the Romans, including the ability to construct a fortified camp every night while on the march. The regular presence of combat engineering crews within field armies, itself a major military innovation, greatly increased the capabilities of tactical combat units.
Among the most difficult tasks of any commander was the ability to control his tactical combat units once committed to battle. For the most part, armies tried to control tactical units by semaphore flag signals and sounds from drums and horns. With the exception of the armies of Rome, few ancient armies succeeded very well. Alexander made good use of a corps of staff riders who could ride to the combat units and pass along instructions.The Romans also used this technique but improved on it by having a special signaler within each cohort. In addition, the Roman army stressed small unit tactical proficiency and discipline, and the soldier was well trained to respond instantly to a number of commands given by his unit leader. The result was that no army matched the proficiency of Roman tactical units in their ability to communicate or rapidly switch course while engaged.
While these individual factors contributed significantly to tactical proficiency and flexibility, they could do so only in an army whose tactical proficiency in the larger sense was already relatively sophisticated. The evolution of tactics over nearly 1,500 years is a fascinating tale of armies increasing their combat power by improving upon small unit tactics. The evolution of tactics proceeded in stages, each stage building upon solutions to problems confronted by the limitations of the previous stage. The results were evident as early as the 14th century B.C. when the Egyptian army first began to learn how to control large units of different combat capabilities, providing evidence of the emergence of a genuine combined arms capability.
The earliest armies were essentially infantry forces with little in the way of other tactical capability. While the early Egyptian army organized its infantry forces by the types of weapons they carried, this practice did little to increase tactical proficiency. The result was packed infantry formations that could hardly move once arrayed for battle. When rival infantry formations clashed and one side broke, the victor had no opportunity to pursue the defeated and increase the casualty rate. This situation changed with the Egyptian adoption of the chariot.
The chariot introduced a radically new tactical capability to the battlefield: mobility. The chariot added a new dimension to the traditional use of shock tactics and, when equipped with archers armed with the composite bow, provided the world's first mobile firing platform. It was the only weapon that could participate in all phases of the battle with equal effectiveness. Its archer crews could engage the enemy at long range. Upon closing, the crews switched to the javelin and axe and attacked as mobile infantry. Once the enemy infantry was scattered, the chariot could be used to mount a truly lethal pursuit. Moreover, the chariot could be used to inflict surprise, a tactic which had never been possible before with packed infantry units. The chariot also allowed another major innovation, the use of mobile reserves that could be committed at a propitious moment to turn a flank or exploit a breakthrough. It became the elite striking arm of the Egyptian armies and greatly expanded the tactical capabilities of Egyptian combat units.
The tactical proficiency of the Assyrian army relied upon providing a mix of units acting in concert. The infantry remained the major shock force of the army. The normal infantry unit was a highly trained maneuver company that could be easily tailored into units of 50-200 men, depending upon the tactical requirements of the moment. The firepower of Assyrian archer companies was increased by as much as 40 percent by introducing an innovation in the shoulder quiver that allowed the arrows to be brought within rapid reach of the bowman. The Assyrian chariot was a large and heavy vehicle that was pulled by three horses and carried a crew of four. Its tactical role was quite different; it maximized the role of shock. The idea was to attack enemy formations from as many directions as possible. Once engaged the crews dismounted and fought as infantry. The Assyrians were the first to introduce the use of mounted infantry, and their use of the chariot strongly parallels the use of armored personnel carriers in modern armies.
The large scope of military action forced the Assyrians to fight in all types of terrain, a condition to which the heavy chariot was often ill-suited. A major Assyrian revolution in battlefield capability was the invention of cavalry. Assyrian cavalrymen used the saddle girth, crupper, and breast strap to stabilize the rider, and the horse was controlled by the leg and heel pressure of the boot. (The spur and stirrup had not yet been invented.) These innovations made possible the first use of mounted archers, the famed "hurricanes on horseback" of the Old Testament. In set-piece battle the cavalry was used to pin the enemy flanks and to take up blocking positions to prevent a retreat. Once in position behind the enemy, the cavalry acted as an anvil against which the chariot and infantry units could drive the enemy. The ability of the horse to traverse uneven terrain made the cavalry especially lethal in pursuit. This same ability made cavalry forces highly flexible and valuable for reconnaissance in force and for providing flank security for the army on the march, two new tactical capabilities.
The Persians expanded the role of the cavalry in their fighting formations. By the time of Cyrus the Persian army's ratio of cavalry to infantry was 20 percent cavalry and 80 percent infantry. It was the largest cavalry force in the world. Although an elite force, Persian cavalry was used primarily to draw the enemy into infantry battle. The weakness of the Persian army, however, was its lack of heavy infantry, and the army usually relied upon sheer numbers to carry the day. Most Persian engagements were with tribal armies that also lacked heavy infantry and the capacity for ground maneuver. Whenever it confronted the heavy infantry of the Greeks, however, the Persian army was almost always defeated. The Greeks had discovered the secret of heavy infantry formations, and in the hands of Alexander, the secret revolutionized small unit tactics.
Heavy infantry had been the mainstay of Greek military tactics in the classical period. The heavily armored hoplite fighting in tightly packed phalanxes had the single advantage of being almost impervious to cavalry attack. The phalanx's major disadvantage was its inability to maneuver and conduct a pursuit. Under Alexander the phalanx was made even heavier. The densely packed formations of the Macedonian phalanx were armed with a 13-foot-long spear called the sarissa, which weighed almost 18 pounds. Although trained in a number of maneuver drills and battle formations, the Macedonian phalanx was, on balance, even less maneuverable than the old hoplite phalanx. Yet, in Alexander's hands, its very stability gave it new tactical value.
Alexander's tactical contribution was to reduce the role of infantry as the primary striking and killing arm of the army. He used his heavy infantry formations to anchor the center of the line and to act as a platform for the maneuver of his primary striking arm, the heavy cavalry armed with the javelin. Alexander coupled this new tactical idea with another, the oblique formation. The infantry was not the foremost frontal point of the line but held back obliquely in the center while the heavy cavalry deployed in strength on the right, connected to the infantry by a hinge of elite cavalry. (General Schwarzkopf's tactical maneuver in the Persian Gulf war was essentially a copy of the Alexandrian model.) The idea was to engage the enemy on the flank and force him to turn toward the attack. As the cavalry pressed the right, the slower infantry advanced in hedgehog formation toward the enemy center. If the enemy flank broke, the cavalry could envelop while the infantry closed toward the center, using the infantry as an anvil against which the cavalry could hammer the enemy. If the flank held, the enemy still had to deal with the shock power of the infantry as it fell upon its center. Alexander was the first to use cavalry as the primary combat arm of an ancient army, and bequeathed the lesson to future armies that cavalry is always to be used in concert with infantry. When both Wellington and Ney forgot this lesson at Waterloo, the result was disaster for both the British and French cavalry forces.
The tactical proficiency of ancient armies had gone through several phases. First was the primacy of infantry; then the Egyptian use of the chariot introduced the new element of mobility to the battlefield. The Assyrians found a new role for the chariot, mounted infantry, but relied instead upon cavalry to provide mobility and flexibility. The great reliance upon cavalry by the Persians led to the neglect of heavy infantry, and Alexander's use of heavy, slow infantry formations as a platform of maneuver signaled the leading role of cavalry as the primary striking force of the ancient armies. In each phase of tactical development, the role of infantry as the main maneuver and killing element of the battlefield declined. How much more surprising, then, that the next major army to appear on the ancient battlefield found its primary strength in the maneuverability and killing power of heavy infantry formations while relegating cavalry to a secondary role.
The spine of the Roman army was its heavy infantry formations. Unlike infantry formations of the past, the Roman maniples and, later, the heavier cohorts, were more maneuverable than any infantry formations that the world had seen. They also surpassed the killing power of earlier infantry formations to an almost exponential degree. The tactical proficiency and lethality of the Roman legion were not surpassed by another army for almost fifteen hundred years. The secret of the Roman killing machine was that the Roman soldier was the first to fight within a combat formation while at the same time remaining somewhat independent of its movement as a unit. He was also the first soldier to rely primarily upon the sword, the dreaded gladius, instead of the spear. The Roman gladius was responsible for more deaths on the battlefield than any other weapon until the invention of the firearm!
The basic tactical unit of the Roman army was the maniple ( literally, "handfuls"), somewhat equivalent to the modern infantry company, with a strength of 160 men. The maniple was divided vertically into two centuries of 80 men each. Each century, as the name implies, was originally comprised of 100 men, but proved too large to be controlled by a single officer. The number was reduced to 80, but the name was retained. By 99 B.C., the army was reformed into cohorts, three maniples to a cohort. Ten cohorts comprised a legion of 6,000 men. This greater size made the legion less brittle to mass attacks commonly used by tribal armies, especially the Gauls and Celts, while retaining the flexibility inherent in the earlier maniple formation.
The infantry formations of earlier armies had been packed masses of men pressed against each other with no spacing between individual soldiers or other units. The result was virtual tactical immobility on the battlefield. The Roman innovation was to build in spaces between soldiers and units, thereby greatly increasing tactical flexibility and mobility. Each maniple deployed as a small, independent phalanx with a 20-man front and 6-man depth, much lighter than earlier formations. The spacing between each soldier was sufficient to allow independent movement and fighting room within an area of 5 square yards. This allowed the soldier greater room to wield his sword. The soldier could move freely over 5 square yards of ground, seeking and destroying individual targets from all directions. Each maniple was laterally separated from the next by 20 yards, a distance equal to the frontage of the maniple itself. The maniples in each line were staggered, with the second and third lines covering the gaps left in the lines to their front. Each line of infantry was separated from the next by an interval of approximately 100 yards. This quincunx or checkerboard formation provided maximum tactical flexibility for each maniple and allowed it to deliver or meet an attack from any direction while delivering maximum killing power.
Tactical flexibility was increased by the relationship between the lines of infantry. If, after the first line engaged, it was unable to break the enemy formation or grew tired, it would retire on command in good order through the gaps left in the second line. The second line then moved to the front and continued the attack. This maneuver could be repeated several times with the effect that the Roman front line was always comprised of rested fighting men. The ability to maneuver through one's own lines offered yet another tactical innovation. The inability of earlier infantry formations to replace the men in the front ranks often turned the defeat of the front rank into a rout of the whole unit. No army until the time of Rome had learned how to break contact and conduct a tactical retreat in good order. The ability of individual lines to pass to the rear, withdrawing through the gaps, allowed the Romans to master the art of disengagement and tactical withdrawal. Few armies would achieve this ability again until the time of Napoleon.
Unlike earlier infantry formations, the Roman maniples could operate totally independently of one another. Since their strength rested in flexibility and not mass, they could also maneuver rapidly when placed on their own. This ability allowed Roman commanders to make maximum use of the element of surprise, something not achievable by infantry forces in earlier armies. A commander could position a few spare maniples in hidden positions, often at the flanks, and even attempt to insert them to the rear of the enemy. Once the main forces engaged, these maniples could be brought into action by flag signals and surprise the enemy with an attack from an entirely different direction. In rough terrain maniples could be used to guard approaches to the battlefield, secure a bridge or crossroad, or conduct a reconnaissance in force. Later, when the maniple formations gave way to the cohorts, the Romans learned to assemble these large (about 600 men) formations in any combination of lines, squares, rectangles, or circles. The result was an increase in combat power while retaining the maneuverability and flexibility of the old maniple. The Roman infantry formations were the most tactically flexible and maneuverable of all infantry formations produced by the armies of the ancient world, and they added a new tactical dimension to war.
The resurgence of infantry as the primary tactical killing arm inevitably reduced the role of cavalry to a secondary one. Roman infantry ruled supreme in the ancient world for almost half a millennium until its fatal defeat at the Battle of Adrianople. The defeat of Roman infantry at the hands of barbarian cavalry shook the tactical thinking of the ancient world. Followed as it was by 100 years of invasions by tribal armies that stressed cavalry, the empire in the West collapsed, and with it went the primacy of infantry. The death of disciplined infantry forces was a natural consequence of the social and military superiority of the new tribal states of Europe. Infantry decayed, and the primacy of cavalry was complete. The Battle of Hastings in 1066 in which an infantry force was massacred by a cavalry army settled the question for hundreds of years.
During the Middle Ages the armored knight became the prototype of the successful warrior, and infantry all but disappeared. The Mongol threat to Europe reinforced the idea that infantry was no longer an effective fighting arm, and the European armies focused more on the role of the armored mounted soldier. Tactics of any sort declined greatly, so much so that most battles of this period could be described as little more than semiorganized brawls. Although the Swiss had shown at Laupen (1339) that a disciplined infantry force could deal effectively with cavalry, and the Battle of Crecy (1346) demonstrated cavalry's vulnerability to the new long-range weapon -- the long bow -- cavalry remained supreme. The resurgence of infantry and tactical flexibility did not begin to reappear until the invention of the musket. And even then it took almost another 200 years before infantry could be reemployed with a skill resembling that of the ancient armies.