Chapter 3 - The Military Revolution
Logistics and Transport
As the size of armies and the scope of battles increased, ancient armies had to master the task of logistically supporting these armies in the field. The logistical feats of ancient armies were often more difficult and often achieved more proficiently than in armies of the 19th century, when the railroad, mass production of weapons, standard packaging, and tinned and condensed food made the problem of supply considerably easier. The need to support armies in the field for months, sometimes years, was a function of the rise of the imperium. Armies now had to conduct combat operations over far wider areas for longer periods than ever before.
Changes in the composition of military forces also added to the logistics burden. The development of the chariot, for example, required Egyptian forces to maintain repair depots and special mobile repair battalions to ensure that the machines remained functional on the march. The Assyrian invention of large cavalry squadrons brought into existence a special branch of the logistics train to ensure that the army could secure, breed, train, and deploy large numbers of horses to support these new forces. This special logistics branch, the musarkisus, was able to obtain and process 3,000 horses a month for the Assyrian army. It was not until the time of Napoleon that Western armies could once again equal this logistical feat. The integration of chariots with cavalry also forced the Assyrian army to become the first to learn how to sustain two types of transport. Advances in siegecraft required that armies transport siege towers and engines within their baggage trains, and artillery, introduced under the Greeks and brought to perfection under the Romans, added yet another requirement to transport catapults and shot. The need to manufacture, issue, and repair new iron weapons in unprecedented numbers required yet more innovations in logistics. In the Assyrian army the production and storage of weapons became a central feature of the army's logistical structure. A single weapons room in Sargon II's palace at Dur-Sharrukin contained 200 tons of iron weapons, and similar weapons warehouses were scattered throughout the empire. Of all the achievements of the ancient armies, those in the area of logistics often remain the most unappreciated by modern military planners.
Among the more important requirements of the logistics trains of ancient armies was the need to supply large numbers of men with adequate food and water. The animals required to haul supplies also had to be fed. The hot and dusty climate of the Middle East made the physical maintenance of the soldier's body even more difficult on the march. In this climate a soldier required 3,402 calories a day and 70 grams of protein to sustain him in minimal nutritional condition. In addition, a soldier required nine quarts of water a day. Modern analysis reveals that the standard ration of three pounds of wheat a day produced only 2,025 calories, insufficient to maintain even minimal nutritional requirements for very long. Thus, Alexander's army of 65,000 men required 195,000 pounds of grain and 325,000 pounds of water to sustain it for a single day! The army also required 375,000 pounds of forage per day to sustain cavalry, baggage, and transport animals. The ability of ancient armies to provide these requirements was nothing short of amazing.
Since the Bronze Age, the standard means of transport for the Egyptian army was the donkey. In Sumer, the solid-wheeled cart drawn by the onager was used very early in the period. At the Battle of Kadesh, Ramses II revolutionized Egyptian logistics by introducing the ox-drawn cart, which quickly became the standard mode of military logistical transport for almost a thousand years. Xenophon recorded that the normal pack load for a single ox-drawn cart in Greek armies was 25 talents, or approximately 1,450 pounds. Studies from World War I by the British War Office note that a mule could carry about three hundred pounds, and the camel just slightly less. The Persians used teams of oxen to haul their large wooden siege and mobile towers. Xenophon noted that 16 oxen were required to pull the tower, which weighed approximately 13,920 pounds!
While the ox-cart allowed armies to move larger loads, it slowed their rate of movement to a crawl. It is important to remember that there were few packed roads and none of the paved roads that were later introduced by the Romans. Most military movement was done across country or, less frequently, on narrow, foot-worn paths where width reduced the speed and flexibility of movement even more. In addition, the animal collar had not been invented yet and harnesses that pressed on the windpipes of the baggage animals increased their rate of physical exhaustion. Under the best of conditions an ox-cart could travel two miles an hour for 5 hours before the animals became exhausted. Moreover, ox-carts generated their own logistical burden. Carts required drivers and, because they needed constant repair, a large corps of repairmen. Repairs required tools and lumber, all of which further increased the logistics load of the army.
As armies grew in size, the logistical burden threatened to reduce drastically their rate of movement and operational flexibility. The introduction by the Assyrians of the horse to military operations allowed a slight increase in logistics capacity, as did their innovation of using the camel as a military beast of burden. Five horses could carry the load of a single ox-cart but could move the load at four miles an hour for 8 hours. Equally important, the horse could move easily over all types of terrain, and five horses required only half the amount of forage required to feed a team of two oxen. Thus, the ox-cart could move a thousand pound load only 10 miles per day while a horse team could move the same load 32 miles per day at twice the speed on half the forage. The Assyrians never really reduced their primary reliance upon ox-carts, however, and the major introduction of the horse to the logistics train grew only gradually under the Persians while finally reaching its height under Philip II and Alexander of Macedon and, later, the Romans.
The Persian army introduced a major innovation in logistics. While the Egyptians had sometimes used small coastal vessels to supply their armies, the Persians were the first to introduce a large-scale navy used primarily in support of ground operations. The Persians were not much as sailors themselves, but they took full advantage of the shipbuilding and maritime skills of the peoples of their coastal provinces. They closely supervised the design of special ships to transport infantry, horses, and supplies, including shallow-draft vessels for use on rivers. Herodotus recorded that during Xerxes' expedition against the Greeks in 481 B.C., the Persians deployed 3,000 transport ships to sustain the army. Coupled with their extensive use of the horse in the supply chain, the supply system of the Persian army was more effective than anything the world had ever seen and allowed the world's largest armies to remain deployed far from home for months on end.
By the time of Alexander the logistical trains of ancient armies had matured to the point where they could regularly supply large armies for longer periods; however, the problem of speed and flexibility of movement over rough terrain remained. The Roman supply system was qualitatively different from that faced by the empires of the past. The great distances encompassed by the Roman empire required speed of movement even more than Alexander did. Philip of Macedon was the first to solve the problem.
Philip discontinued the age-old practice of allowing soldiers to take along attendants, wives, girlfriends, and other service providers when they went to war. Under the old system, an army of 30,000 fighting men would have dragged along behind it almost the same number of camp followers. By forbidding the presence of these people, Philip reduced the logistics burden of his army by almost two-thirds. This change increased the combat power of the army and increased its rate of march. Alexander's army could routinely move at 13 miles a day, and separate cavalry units could cover 40 miles a day. These rates were simply unheard of before Philip's reforms.
Philip further increased rates of movement by eliminating the ox-cart as the standard logistics vehicle and replacing it with a mixture of horses and mules. A few ox-carts were still used to transport the wounded and disassembled siege engines and artillery pieces. This innovation more than tripled the army's rate of movement and increased its ability to maneuver over rough terrain. Like the great Roman military reformer Gaius Marius some 200 years later, Philip gained even greater speed and mobility for his logistics train by turning his soldiers into beasts of burden.
Both Alexander and the Romans made maximum use of the carrying capacity of their soldiers to increase logistics capability, and the soldier's load has been increasing ever since. Both the Greek and Roman soldier routinely carried 60-70 pounds on his back. By comparison, American troops in the Normandy invasion carried 82 pounds of equipment and supplies, while the soldiers at Waterloo carried 60-70 pounds. The British soldiers who stormed Bunker Hill hauled 80 pounds. Cavalry soldiers could carry even more by using their horses as transport. With soldiers carrying one-third the load that would be normally hauled by animals, an army of 50,000 men required 6,000 fewer pack animals than it would have needed, along with 240 fewer animals to haul the feed for the other animals. By requiring the soldier to carry his own equipment and food, Alexander created the lightest, most mobile, and fastest army the world had ever seen. These same reforms introduced in the Roman army by Marius in 99 B.C. produced the same results.
In the early Iron Age the ability to provide supplies for any army was hampered by the lack of any genuine medium of exchange. Most of the early Iron Age economies functioned on a barter system so that most military supplies were obtained as levies against various producers. The Persian invention and introduction of a uniformly acceptable gold currency changed this situation. Darius I was the first monarch to coin money, and used a standard coin weighing 130 grains of gold. Backed by the enormous Persian gold reserves, the daric became the only gold currency of the early ancient world and could be spent anywhere. Military establishments could now pay for what they needed. The use of currency also led to the establishment of uniform weights and measures, which allowed logistical planners to obtain military supplies in precise amounts and weights. Merchants emerged whose business was to provide military supplies on a regular basis, an activity that brought into existence the first military contractors. Moreover, money could be used to provision an army even when in hostile territory. The businessmen of Thrace and Macedonia sold supplies to Darius during the Greek campaign, and when the Persian army crossed the Sinai in its campaign against Egypt, local Egyptian merchants provided and prepositioned thousands of water skins at designated points in the desert to make the crossing possible.
In providing logistical support, imperial powers usually had the advantage of internal lines of communication, which made supply movement easier. Moreover, like Napoleon two thousand years later, armies often prepositioned stocks of supplies at the empire's rim in an attempt to reduce travel distances. Once in enemy territory, however, like every army after them until the very modern age, armies lived mostly off the land and captured enemy stores. This practice explains the penchant of armies to attack cities even when it made little tactical sense. A review of Gustav Adolphus' route of march during the Thirty Years War (1618-48) shows precisely the same propensity for exactly the same reasons. Finally, armies often timed campaigns to take maximum advantage of the seasons to ensure an adequate food supply in captured enemy areas. Taken together, the logistics capabilities of ancient armies were excellent, often managing staggering feats of supply that only rarely were duplicated by armies before the 19th century.