The Romans’ success in conquering and maintaining their enormous empire lay partly in their military culture, their weapons and their training. Rome’s ability to provision large armies at long distances was, however, equally as, or more important to its success. The military history of Rome is not one of continuous victory: indeed the Romans often won wars because, after losing battles—and sometimes entire armies and fleets—they could keep replacing them until the enemy was defeated. Polybius, a keen observer of the Roman military at its height, remarked that “the advantages of the Romans lay in inexhaustible supplies of provisions and men.”
A sophisticated logistical system allowed the Romans to exploit their military resources effectively. The Romans recognized the importance of supply and used it both as a strategic and a tactical weapon and the necessities of military supply influenced and often determined the decisions of the Roman commanders at war. Plutarch even mentions the military slang term for such tactics: “kicking in the stomach” (eis tên gastera enallonomenos). Frontinus cites Caesar, certainly Rome’s greatest general, on the use of logistics in military strategy:
I follow the same policy toward the enemy as did many doctors when dealing with physical ailments, namely, that of conquering the foe by hunger rather than by steel. Logistics in Campaign Planning Traditionally, Roman campaigns began on March 1st: in part to ensure the availability of fodder.
The Romans paid close attention both to raising armies and to the preparations for supplying them. Their habitually careful arrangements made a strong impression, and, given the general neglect of logistics in military history, our sources mention such planning remarkably often. For example, Polybius describes the large-scale Roman preparations for a Gallic invasion as early as 225 B. C.:
[The consuls] enroll[ed] their legions and ordered those of their allies to be in readiness. . . . Of grain, missiles and other war materiel, they laid in such a supply as no one could remember had been collected on any previous occasion.
There are many other examples both in the Republican and the Imperial periods.
Commanders naturally wanted to complete their logistical preparations before operations began. When Quinctius Flamininus was preparing his campaign against Nabis, the tyrant of Sparta, in 195 B. C., the arrival of allied troops, including Macedonians, completed his authorized force. Nevertheless, he still waited until the arrival of the supplies (commeatus) requisitioned from the neighboring Greek states before beginning his offensive. At times, troops were moved first and supplies sent after them. When Sulla had obtained the command of the First Mithridatic War, he marched his army over to Greece and then summoned money, auxiliary troops and supplies from Aetolia and Thessaly.
Some wars broke out unexpectedly and preparations had to be made in haste. Sallust notes that when the consul Spurius Postumius Albinus determined to reopen hostilities with Jugurtha, he “hastened to transport to Africa provisions (commeatus), money for paying the soldiers, and other apparatus of war.” The frequency of Roman conflict, and the experience of Roman officials with warfare, made such impromptu preparations much easier. Other times, military campaigns were planned years in advance.
The Security of Supply Lines
Ensuring that the army continued to receive supplies, despite an enemy’s attempts to interrupt them, remained an important priority in Roman warfare in every period. Provisions reached the army in a variety of ways: by sea and river, overland and through foraging and requisition. In each of these circumstances, enemy action was a threat, and the Romans had to deploy military forces, as well as the application of strategy and tactics, to meet this threat. Rome often found it necessary to prevent the enemy plundering Roman or allied territory: it is noteworthy that the fleet of Gaius Duilius, which won the first major Roman victory of the First Punic War at Mylae (260 B. C.), was sent out to prevent the Carthaginians from plundering the territory of a Roman ally.
Security of Waterborne Transport
Protecting sea-borne transport was vitally important in wartime: enemy action could seriously threaten the army’s supply shipments. There are many instances of such threats. In 217 B. C., for example, the Roman grain fleet supplying the army in Spain was captured by the Punic fleet. A Roman task force was immediately mobilized to set out in pursuit, but the damage had already been done. Plutarch notes that the Macedonian king Perseus during his war against the Romans (172–167 B. C.):
. . . made an unexpected attack upon the Roman fleet which was lying at anchor near Oreus, seized twenty ships of burden with their car- goes, and sank the rest together with the grain that filled them. . . .
The navy of Antiochus III, operating from the Hellespont and Abydos during the war of 192–189 B. C., made frequent raids (excursiones) against Roman cargo ships (onerariae) supplying their army in Greece. Later, Mithridates used his naval superiority in the eastern Mediterranean to cut off supplies to Sulla’s forces in Greece in 87–85 B. C. Attacks on sea-borne supply were important elements in the Civil Wars of the Late Republic. In 42 B. C., a Republican fleet under Statius defeated Dolabella’s fleet at Laodicea, cutting him off from supplies. When Octavian sent a large force by sea to reinforce and resupply the Caesarean army at Philippi, it was attacked and destroyed by the Republican navy.
The Romans routinely used their fleet to protect supply transports in wartime. As early as the First Punic War, the Romans assigned a fleet of 120 warships to provide a convoy for merchant ships bringing supplies for the siege of Lilybaeum (249 B. C.). When the commander of the fleet in 209 B. C., Marcus Valerius Laevinus turned some ships over to the consul Quintus Fabius Maximus for use in the assault on Tarentum, they are called by Livy “the ships which Laevinius had for protecting the supply lines (tutandis commeatibus).” Such protection continued in the late Republic: Sallust, in a speech attributed to the consul Gaius Cotta, and set in 75 B. C., refers to the fleet which “guarded our supplies (commeatus tuebatur).”
Such naval escorts were not always successful. The convoy protecting supplies going to Lilybaeum in 249 B. C., mentioned above, did not prevent the Carthaginians from attacking and seizing several of the merchant vessels. The threat of attack was sometimes more destructive than the attack itself: trying to avoid attack by Carthaginian warships, a Roman supply fleet placed its ships in a dangerous anchorage where a storm destroyed the entire fleet including all the army’s supplies. Whenever possible, a fleet put supplies put ashore before a battle. To prevent them from falling into enemy hands commanders of escorts might scuttle conveyed merchant ships, as the Pompeian admirals Lucretius and Minucius did during the Dyrrachium campaign of 48 B. C. 26 Despite the dangers of attack, supplies transported by sea were generally safer from attack than those sent overland, a point made by Tacitus.
Security of Overland Supply
The army provided escorts for supply convoys bringing provisions to troops in garrison even during peacetime, albeit on a limited scale. An incident from the anti-Roman uprising of Athrongaeus in Palestine around 4 B. C. illustrates the small size of such peace- time escorts. Josephus reports that a single century (80 men at full strength) was escorting a convoy of grain and arms to a legion stationed in Jerusalem, when the rebels ambushed the column near Emmaus. The Romans lost half the century and only the intervention of King Herod’s army saved the rest.
Obviously, moving provisions from the operational base to the army over supply lines provided ample opportunities for attack. Due to the increased danger in war, convoy escorts were, of course, considerably larger than in peacetime. A tribune commanded the forces that escorted a supply convoy bringing provisions to the army of Pompeius Aulus in Spain in 141 B. C. Appian does not give the size of the escort, but a tribune would have commanded at least several centuries and possibly a cohort or more.
An escort’s size was not the only factor in successful defense of a convoy. While accompanying a supply convoy to Lucullus’s army from Cappadocia in 71 B. C., a Roman force defeated an attack by Mithridates’s cavalry: the Pontic force had attacked the convoy in a defile, a more easily defensible position, instead of waiting until it reached open country. An escort also had to maintain a disciplined defense cordon, even if the column was proceeding to pick up sup- plies. Tacitus notes the lack of security in an unloaded supply column going to Novaesium from the Roman forces at Gelduba in 69 A. D., during the revolt of Julius Civilis. The troops assigned to defend it moved as if there were no danger:
. . . the cohorts escorting [the convoy] were proceeding as if in time of peace, that there were few soldiers with the standards, that their arms were being carried in carts (vehicula) while they all strolled along at will, he drew up his forces and attacked them, sending first some troops to occupy the bridges and narrow parts of roads.
The column was unable to make it to Novaesium and had to fight its way back to Gelduba without fulfilling its mission. In order to secure its supply lines, an army had to pacify the area between the operational base and the tactical base. This is why Vespasian did not immediately attack Jerusalem when he arrived on the scene in 67 A. D.: if he left hostile forces behind him, in Galilee and Samaria, the rebels would have been in a position to cut off his supply lines. Therefore, he spent an entire campaigning season taking important fortresses in the north of Palestine.
Providing a series of depots between the operational and tactical base was not only a question of “leap-frogging” supplies forward. Depots were generally placed within fortifications, as at Rödgen and South Shields and they served to secure provisions from enemy attack. Therefore, the sources often refer to them as “forts” (castella or phrouria). Vegetius describes this practice:
Among the things particularly incumbent upon a general . . . is to see that the transportation of grain and other provisions . . . is rendered secure from hostile attack. The only way to achieve this is to plant garrisons at suitable points through which our supply-trains pass. These may be cities or walled forts. If no old fortifications are available, temporary forts (castella) are established in favorable positions [and] a number of infantry and cavalry stationed in them on outpost duty provide a safe passage for supplies.
Brutus used fortified lines to protect his supply lines at Philippi (42 B. C.).
The use of fortified depots considerably reduced the risk of attack to supply lines. Once a rear area had been pacified, though, the danger of convoyed supplies, which at first glance seem very vulnerable, was actually rather small. Lacking firearms or explosives, the ambushing party in antiquity usually had to rely on superior numbers to overwhelm a convoy. Even if the enemy knew the likely route of a convoy, the exact time of its movement would not be predictable, so a large ambushing force would have had to wait in enemy territory, itself vulnerable to surprise attack.
Naturally, armies have a tendency to use their worst troops to garrison depots and operational bases, not to mention escort duty, leaving the best soldiers for combat. Livy explicitly states that after the consuls filled their legions with the best troops, they assigned the “surplus” (ceteri ) to garrison duty. In the Republican period, the Romans sometimes used their least reliable Italian allies to defend supply lines, sometimes with unfortunate results. In 218 B. C., Dasius of Brundisium commanded the garrison of Clastidium, in which a great quantity of grain had been stored for the Roman army. He betrayed the city to Hannibal for 400 gold pieces. The city’s capture not only hurt the Romans, but relieved the Carthaginians of considerable supply difficulties. When Manlius Vulso set up an operational base on the Lake of Timavus in his Istrian campaign of 178 B. C., he garrisoned it with a single reserve cohort (repentina cohors) and a few legionary centuries. The Istrians, seeing the weakness of the Roman defense, attacked the base and captured it. Only the barbarian drunkenness that followed, and the timely arrival of Gallic auxiliaries and of part of another legion (which had been foraging nearby) restored the situation, and the base, to the Romans.
Since Roman marching camps also functioned as supply bases, camp security was especially important. The Romans were justifiably famous for their security measures while encamping. Such measures involved both fortification and maintaining the discipline necessary to proper security. This system sometimes broke down, as it did in Albinus’s army in Numidia. Sallust notes that in this case:
. . . [his] camps were not fortified, nor was watch kept in a military fashion, men absented themselves from duty whenever they pleased.
It was no doubt at least partly for logistical reasons that the consul Caecilius Metellus reestablished security in his famous reform of the army in 109 B. C.