Roman infantry versus the Macedonian phalanx Prior to the rise of Rome, the
Macedonian phalanx was the premier infantry force in the Western World. It had proven itself on the battlefields of Mediterranean Europe, from
Sparta to
Macedonia, and had met and overcome several strong non-European armies from Persia to Northwest India. Packed into a dense armoured mass, and equipped with massive pikes 12 to in length, the phalanx was a formidable force. While defensive configurations were sometimes used, the phalanx was most effective when it was moving forward in attack, either in a frontal charge or in "oblique" or echeloned order against an opposing flank, as the victories of
Alexander the Great and Theban innovator
Epaminondas attest. When working with other formations (light infantry and cavalry) it was, at its height under Alexander, without peer. Nevertheless, the Macedonian phalanx had key weaknesses. It had some manoeuvrability, but once a clash was joined this decreased, particularly on rough ground. Its "dense pack" approach also made it rigid. Compressed in the heat of battle, its troops could only primarily fight facing forward. The diversity of troops gave the phalanx great flexibility, but this diversity was a double-edged sword, relying on a mix of units that was complicated to control and position. These included not only the usual heavy infantrymen, cavalry and light infantry but also various elite units, medium armed groups, foreign contingents with their own styles and shock units of
war-elephants. Such "mixed" forces presented additional command and control problems. If properly organized and fighting together a long time under capable leaders, they could be very proficient. The campaigns of Alexander and
Pyrrhus (a Hellenic-style formation of mixed contingents) show this. Without such long-term cohesion and leadership, however, their performance was uneven. By the time the Romans were engaging against Hellenistic armies, the Greeks had ceased to use strong flank guards and cavalry contingents, and their system had degenerated into a mere clash of phalanxes. This was the formation overcome by the Romans at the
Battle of Cynoscephalae. The Romans themselves had retained some aspects of the classical
phalanx (not to be confused with the Macedonian phalanx) in their early legions, most notably the final line of fighters in the classic "triple line", the spearmen of the
triarii. The long pikes of the
triarii were to eventually disappear, and all hands were uniformly equipped with short sword, shield and
pilum, and deployed in the distinctive Roman tactical system, which provided more standardization and cohesion in the long run over the Hellenic type formations. Phalanxes facing the legion were vulnerable to the more flexible Roman "checkerboard" deployment, which provided each fighting man a good chunk of personal space to engage in close order fighting. The manipular system also allowed entire Roman sub-units to manoeuvre more widely, freed from the need to always remain tightly packed in rigid formation. The deep three-line deployment of the Romans allowed combat pressure to be steadily applied forward. Most phalanxes favoured one huge line several ranks deep. This might do well in the initial stages, but as the battle entangled more and more men, the stacked Roman formation allowed fresh pressure to be imposed over a more extended time. As combat lengthened and the battlefield compressed, the phalanx might thus become exhausted or rendered immobile, while the Romans still had enough left to not only manoeuvre but to make the final surges forward. Rome however had blunted Pyrrhus' hosts prior to the rise of Hannibal, and given their advantages in organization, discipline, and resource mobilization, why did they not make a better showing in the field against the Carthaginian, who throughout most of his campaign in Italy suffered from numerical inferiority and lack of support from his homeland? Hannibal's individual genius, the steadiness of his core troops (forged over several years of fighting together in Spain, and later in Italy) and his cavalry arm seem to be the decisive factors. Time after time Hannibal exploited the tendencies of the Romans, particularly their eagerness to close and achieve a decisive victory. The cold, tired, wet legionaries that slogged out of the Trebia River to form up on the river bank are but one example of how Hannibal forced or manipulated the Romans into fighting on his terms, and on the ground of his own choosing. The later debacles at
Lake Trasimene and
Cannae, forced the proud Romans to avoid battle, shadowing the Carthaginians from the high ground of the Apennines, unwilling to risk a significant engagement on the plains where the enemy cavalry held sway. Roman sources reflect on the prejudices of their times, but nevertheless testify to the Gauls' fierceness and bravery. :Their chief weapons were long, two-edged swords of soft iron. For defence, they carried small wicker shields. Their armies were undisciplined mobs, greedy for plunder... Brave to the point of recklessness, they were formidable warriors, and the ferocity of their first assault inspired terror even in the ranks of veteran armies.
Early Gallic victories Though popular accounts celebrate the legions and an assortment of charismatic commanders quickly vanquishing massive hosts of "wild barbarians", Rome suffered a number of early defeats against such tribal armies. As early as the Republican period (circa 390–387 BC), they had
sacked Rome under
Brennus, and had won several other victories such as the
Battle of Noreia and the
Battle of Arausio. The foremost Gallic triumph in this early period was "The Day of Allia" (July 18) when Roman troops were routed and driven into the Allia River. Henceforth, July 18 was considered an unlucky date on the
Roman calendar. '' found at
Dura Europos Some writers suggest that as a result of such debacles, the expanding Roman power began to adjust to this vigorous, fast-moving new enemy. The Romans began to phase out the monolithic phalanx they formerly fought in and adopted the more flexible manipular formation. The circular hoplite shield was also enlarged and eventually replaced with the rectangular
scutum for better protection. The heavy phalanx spear was replaced by the
pila, suitable for throwing. Only the veterans of the
triarii retained the long spearvestige of the former phalanx. Such early reforms also aided the Romans in their conquest of the rest of Italy over such foes as the Samnites, Latins, and Greeks. As time went on Roman arms saw increasing triumph over the Gauls, particularly in the campaigns of Caesar. In the early imperial period, however, Germanic warbands inflicted one of Rome's greatest military defeats (the
Battle of the Teutoburg Forest), which saw the destruction of three imperial legions and was to place a limit on Roman expansion in the West. And it was these Germanic tribes in part (most having some familiarity with Rome and its culture, and becoming more Romanized themselves) that were to eventually bring about the Roman military's final demise in the West. Ironically, in the final days, the bulk of the fighting was between forces composed mostly of barbarians on either side.
Tactical performance versus Gallic and Germanic opponents Gallic and Germanic strengths Whatever their particular culture, the Gallic and Germanic tribes generally proved themselves to be tough opponents, racking up several victories over their enemies. Some historians show that they sometimes used massed fighting in tightly packed phalanx-type formations with overlapping shields, and employed shield coverage during sieges. In open battle, they sometimes used a triangular "wedge" style formation in attack. Their greatest hope of success lay in four factors: (a) numerical superiority, (b) surprising the Romans (via an ambush for example), (c) advancing quickly to the fight, or (d) engaging the Romans over heavily covered or difficult terrain where units of the fighting horde could shelter within striking distance until the hour of decision, or if possible, withdraw and regroup between successive charges. Most significant Gallic and Germanic victories show two or more of these characteristics. The
Battle of the Teutoburg Forest contains all four: numerical superiority, surprise, quick charges to close rapidly, and favorable terrain and environmental conditions (thick forest and pounding rainstorms) that hindered Roman movement and gave the warriors enough cover to conceal their movements and mount successive attacks against the Roman line. Another factor in the Romans' defeat was a treacherous defection by
Arminius and his contingent.
Gallic and Germanic weaknesses Weaknesses in organization and equipment. Against the fighting men from the legion however, the Gauls, Iberians and Germanic forces faced a daunting task. The barbarians' rudimentary organization and tactics fared poorly against the well-oiled machinery that was the
Roman legion. The fierceness of the Gallic and Germanic charges is often commented upon by some writers, and in certain circumstances, they could overwhelm Roman lines. Nevertheless, the in-depth Roman formation allowed adjustments to be made, and the continual application of forwarding pressure made long-term combat a hazardous proposition for the Gauls. Flank attacks were always possible, but the legion was flexible enough to pivot to meet this, either through sub-unit manoeuvre or through the deployment of lines farther back. The cavalry screen on the flanks also added another layer of security, as did nightly regrouping in fortified camps. The Gauls and Germans also fought with little or no
armour and with weaker shields, putting them at a disadvantage against the legion. Other items of Roman equipment from studded sandals, to body armour, to metal helmets added to Roman advantages. Generally speaking, the Gauls and Germans needed to get into good initial position against the Romans and to overwhelm them in the early phases of the battle. An extended set-piece slogging match between the lightly armed tribesmen and the well-organized heavy legionaries usually spelt doom for the tribal fighters. as is the victory of Germanicus at the Weser River and
Agricola against the Celtic tribesmen of Caledonia (Scotland) circa 84 AD.
Weaknesses in logistics. Roman logistics also provided a trump card against Germanic foes as it had against so many previous foes.
Tacitus in his
Annals reports that the Roman commander
Germanicus recognized that continued operations in Gaul would require long trains of men and material to come overland, where they would be subject to attack as they traversed the forests and swamps. He, therefore, opened sea and river routes, moving large quantities of supplies and reinforcements relatively close to the zone of battle, bypassing the dangerous land routes. In addition, the Roman fortified camps provided secure staging areas for offensive, defensive and logistical operations, once their troops were deployed. Assault roads and causeways were constructed on the marshy ground to facilitate manoeuvre, sometimes under direct Gallic attack. These Roman techniques repeatedly defeated their Germanic adversaries. While Germanic leaders and fighters influenced by Roman methods sometimes adapted them, most tribes did not have the strong organization of the Romans. As German scholar Hans Delbruck notes in his "History of the Art of War": :...The superiority of the Roman art of warfare was based on the army organization... a system that permitted very large masses of men to be concentrated at a given point, to move in an orderly fashion, to be fed, to be kept together. The Gauls could do none of these things.
Gallic and Germanic chariots The Gauls also demonstrated a high level of tactical prowess in some areas. Gallic
chariot warfare, for example, showed a high degree of integration and coordination with infantry, and Gallic horse and chariot assaults sometimes threatened Roman forces in the field with annihilation. At the
Battle of Sentinum for example, c. 295 BC, the Roman and Campanian cavalry encountered Gallic war-chariots and were routed in confusiondriven back from the Roman infantry by the unexpected appearance of the fast-moving Gallic assault. The discipline of the Roman infantry restored the line, however, and a counter-attack eventually defeated the Gallic forces and their allies. The accounts of
Polybius leading up to the
Battle of Telamon (c. 225 BC) mention chariot warfare, but it was ultimately unsuccessful. The Gauls met comprehensive defeat by the Roman legions under
Papus and
Regulus. Chariot forces also attacked the legions as they were disembarking from ships during
Caesar's invasion of Britain, but the Roman commander drove off the fast-moving assailants using covering fire (slings, arrows and engines of war) from his ships and reinforcing his shore party of infantry to charge and drive off the attack. In the open field against Caesar, the Gallic/Celtics apparently deployed chariots with a driver and an infantry fighter armed with javelins. During the clash, the chariots would drop off their warriors to attack the enemy and retire a short distance away, massed in reserve. From this position, they could retrieve the assault troops if the engagement was going badly, or apparently, pick them up and deploy elsewhere. Caesar's troops were discomfited by one such attack, and he met it by withdrawing into his fortified redoubt. A later Gallic attack against the Roman camp was routed. Superb as the Gallic fighters were, chariots were already declining as an effective weapon of war in the ancient world with the rise of mounted cavalry. At the
Battle of Mons Graupius in Caledonia (circa 84 AD), Celtic chariots made an appearance. However, they were no longer used in an offensive role but primarily for the pre-battle showriding back and forth and hurling insults. The main encounter was decided by infantry and mounted cavalry. So far the situation looked promising for the warrior host. The
Battle of Gergovia demonstrates that the Gallic were capable of a level of strategic insight and operation beyond merely mustering warriors for an open field clash. Under their war leader
Vercingetorix, the Gauls pursued what some modern historians have termed a "persisting" or "logistics strategy"a mobile approach relying not on direct open field clashes, but avoidance of major battle, "scorched earth" denial of resources, and the isolation and piecemeal destruction of Roman detachments and smaller unit groupings. When implemented consistently, this strategy saw some success against Roman operations. According to Caesar himself, during the siege of the town of Bourges, the lurking warbands of Gauls were: :...on the watch for our foraging and grain-gatherer parties, when necessarily scattered far afield he attacked them and inflicted serious losses... This imposed such scarcity upon the army that for several days they were without grain and staved off starvation only by driving cattle from remote villages. Caesar countered with a strategy of enticing the Gallic forces out into open battle, or of blockading them into submission. At the town of
Gergovia, resource denial was combined with a concentration of superior force and multiple threats from more than one direction. This caused the opposing Roman forces to divide and ultimately fail. Gergovia was situated on the high ground of a tall hill and Vercingetorix carefully drew up the bulk of his force on the slope, positioning allied tribes in designated places. He drilled his men and skirmished daily with the Romans, who had overrun a hilltop position and had created a small camp some distance from Caesar's larger main camp. A rallying of about 10,000 disenchanted Aeudan tribesmen (engineered by Vercingetorix's agents) created a threat in Caesar's rear, including a threat to a supply convoy promised by the allied Aeudans, and he diverted four legions to meet this danger. This, however, gave Vercingetorix's forces the chance to concentrate in superior strength against the smaller two-legion force left behind at Gergovia, and desperate fighting ensued. Caesar dealt with the real threat, turned around and by ruthlessly forced marching once again consolidated his forces at the town. A feint using bogus cavalry by the Romans drew off part of the Gallic assault, and the Romans advanced to capture three more enemy outposts on the slope, and proceeded towards the walls of the stronghold. The diverted Gallic forces returned however and in frantic fighting outside the town walls, the Romans lost 700 men, including 46 centurions. Caesar commenced a retreat from the town with the victorious Gallic warriors in pursuit. The Roman commander, however, mobilized his 10th Legion as a blocking force to cover his withdrawal and after some fighting, the tribesmen themselves withdrew back to Gergovia, taking several captured legion
standards. The vicious fighting around Gergovia was the first time Caesar had suffered a military reverse, demonstrating the Gallic martial valor noted by the ancient chroniclers. The hard battle is referenced by the Roman historian
Plutarch, who writes of the Averni people showing visitors a sword in one of their temples, a weapon that reputedly belonged to Caesar himself. According to Plutarch, the Roman general was shown the sword in the temple at Gergovia some years after the battle, but he refused to reclaim it, saying that it was consecrated, and to leave it where it was. The Gauls were unable to sustain their strategy and Vercingetorix was to become trapped in
Alesia, facing not divided sections or detachments of the Roman army but Caesar's full force of approximately 70,000 men (50,000 legionaries plus numerous additional auxiliary cavalry and infantry). This massive concentration of Romans was able to besiege the fortress in detail and repulse Gallic relief forces, and it fell in little more than a month. At the
Battle of Alesia this mobile approach became overly static. The Gauls gave battle at a place where they were inadequately provisioned for an extended siege, and where Caesar could bring his
entire field force to bear on a single point without them being dissipated, and where his lines of supply were not effectively interdicted. At Gergovia by contrast, Caesar's strength was divided by the appearance of another Gallic force in his rear (the Aeudans) threatening his sources and lines of supply. Together with a strong defensive anvil, (the town) supported by an offensive hammer (the open field forces), and coupled with previous resource denial pressure over time, the Romans were forced to retreat, and the Gallic secured a victory. As one historian notes about the persisting strategy: :But before the defeat at Alesia, Vercingetorix's strategy had driven Cesar from central Gaul... In finding and overwhelming Roman foragers as
Fabius had done to Hannibal's men, the Gauls concentrated against weakness to win many small victories. Their strength in cavalry helped them concentrate rapidly, facilitating the application of the combat element in their strategy, though attacking foragers and grain gatherers were also intrinsic to the logistic aspect of their campaign.
Roman infantry versus mobile and guerilla warfare in Hispania :
The Iberian zone of struggle. The Gallic–Celtic–Iberian peoples, like many other tribes, descended from the general "Celtic" race, put up an obstinate fight against Roman hegemony. Based in
Hispania (what is now Spain and Portugal), they fought continuously, with varying levels of intensity, for almost two centuries, beginning around 218 BC. The initial hegemons of Hispania were the Carthaginians who struggled against various tribes to carve out colonies and a commercial empire, primarily in coastal enclaves. Carthaginian defeats by Rome brought struggle against a new imperium. Tribes such as the
Celtiberi carried out a strong resistance, a struggle later continued by other groups such as the
Lusitani, under
Viriathus. The
Lusitanian War and the
Numantine War are but a few examples of the prolonged conflict, which cut across 20 decades of Roman history. Full conquest was not achieved until the time of
Augustus. The vicious long-term fighting made Hispania a place of dread for the Roman soldier. Historian Sir Edward Creasy, in his
The Fifteen Decisive Battles of the World had this to say about the Iberian conflicts. ::The war against the Spaniards, who, of all the nations subdued by the Romans, defended their liberty with the greatest obstinacy... the Romans in both provinces were so often beaten, that nothing was more dreaded by the soldiers at home than to be sent there... :
Roman tactics. Rome deployed its standard methods, with greater emphasis on blended units of light troops, cavalry and heavy infantry when confronting the guerrilla or mobile tactics used by the
Iberians. Roman fortified camps were also valuable in protecting the troops and providing bases of operation. While combat results were mixed in the open field, the Romans did comparatively well when besieging Iberian cities, systematically eliminating enemy leaders, supply bases and centres of resistance. Destruction of Iberian resources by burning grain fields or demolishing villages also put the native resistance under greater pressure. The operations of Scipio during the
Numantine War illustrate these methods, including a crackdown on lax practices and tightening of discipline. Other Roman tactics touched on the political sphere such as the "pacification" treaties of Gracchus, and treachery and trickery, as in the massacres of tribal leaders by
Lucullus and
Galba under guise of negotiation. Rome frequently capitalized on divisions among the tribes. A "divide and conquer" policy was in use, with competing (and sometimes insincere) treaties being negotiated to isolate targeted groups, and allied tribes being used to subdue others. :
Celtic–Iberian tactics. Fighting for their independence and survival, the Iberian tribes used fortified cities or strongpoints to defend against their enemies and mixed this with mobile warfare in formations ranging from small
guerrilla bands to large units numbering thousands of men. The Celtic/Iberian horsemen, in particular, appear to be more than a match for those of Rome, a fact proved in earlier years by the key role such allied cavalry played in Hannibal's victories. Favourable mobility and knowledge of the local terrain were to help the tribes immensely. One of the most successful ambushes was pulled off by a chieftain named Carus, who liquidated around 6,000 Romans in a combined cavalry-infantry strike. Another was executed by
Caesarus, who took advantage of a disorderly Roman pursuit under
Mummius, to lay a trap that resulted in Roman losses of around 9,000 men. A similar Iberian "turn and fight" gambit is also recorded as being successful against
Galba. Roman arms however triumphed over two grinding centuries of conflict. See ''
Appian's History of Rome: The Spanish Wars'' for a more detailed discussion of individual battles, leaders and engagements. Rome's massive manpower supply was the foundation of this approach. Opponents could be relentlessly weakened and exhausted over the long run. In Spain, resources were thrown at the problem until it yielded over 150 years latera slow, harsh grind of endless marching, constant sieges and fighting, broken treaties, burning villages and enslaved captives. As long as the Roman Senate and its successors were willing to replace and expend more men and material decade after decade, victory could be bought through a strategy of exhaustion. The systematic wastage and destruction of enemy economic and human resources were called
vastatio by the Romans. Crops and animals were destroyed or carried off, and local populaces were massacred or enslaved. Sometimes these tactics were also used to conduct punitive raids on barbarian tribes which had performed raids across the border. In the campaigns of
Germanicus, Roman troops in the combat area carried out a "scorched earth" approach against their Germanic foes, devastating the land they depended on for supplies. "The country was wasted by fire and sword fifty miles round, nor sex nor age found mercy; places sacred and profane had the equal lot of destruction, all razed to the ground..." (Tacitus,
Annals.) The Roman "grind down" approach is also seen in the Bar Kokhba Jewish revolt against the Romans. The Roman commander Severus avoided meeting the hard-fighting Jewish rebels in the open field. Instead, he relied on attacking their fortified strong points and devastating the zone of conflict in a methodical campaign. This "attritional" aspect of the Roman approach to combat contrasts with the notion of brilliant generalship or tactics sometimes seen in popular depictions of the Roman infantry. Some historians note, however, that Rome often balanced brutal attrition with shrewd diplomacy, as demonstrated by Caesar's harsh treatment of Gallic tribes that opposed him, but his sometimes conciliatory handling of those that submitted. Rome also used a variety of incentives to encourage cooperation by the elites of conquered peoples, co-opting opposition and incorporating them into the structure of the Empire. This
carrot and stick approach forms an integral part of "the Roman way" of war.
Resource tactics '' certificate issued under the emperor
Titus As with any military organization, training soldiers/armies requires a number of things and could prove to be quite costly in the long run. The Romans understood this concept very well and realized that training soldiers could include paying for their rations, salary, armour, weapons, and a soldier's honorarium, which was paid to those who received
honesta missio (honourable discharge). With all this in perspective, they realized each individual soldier was a far too valuable resource to waste. They knew the costs they were incurring for each soldier had to be quite similar on their enemy's side. So they developed a tactic that could cause a significant setback or even defeat for their enemy while only creating a limited risk for their own soldiers. This was known as "resource tactics". Standing armies run on their stomachs and their equipment, and both require regular supplies; resource tactics cut off an opponent from their resources in one of three ways: • Attack resource locations: once they conquered territory, the Romans would secure as many resources as they could handle. This allowed them to restock their own supply and prevent the available resources from falling into their opponents' hands. • Intercept supplies while in transit: the Romans would identify their enemies' main supply routes and create a stopping point. Once the enemy was stopped, the Romans would ransack the supply, which would drastically reduce the supplies reaching the enemy. Crassus' force was systematically dismembered by the smaller
Parthian army, who surprised Roman expectations that they would run out of arrows, by arranging for a supply train of ammunition borne by thousands of camels. Roman casualties were approximately 20,000 killed and 10,000 captured making the battle one of the costliest defeats in Roman history. Parthian casualties were minimal.
Successful tactics Clues exist in the earlier campaigns of Alexander the Great against mounted Asiatic warriorsengaging the horsemen with strong detachments of light infantry and missile troops and driving them off with charges by Alexander's heavy cavalry units. The Roman variant, with its large manpower resources, continued the same "combined arms" approach, with a larger role for cavalry as the Empire went on. The Eastern half of the
Roman Empire, particularly, was ultimately to rely mostly on cavalry forces.
Adjustments of Ventidius. The operations of the Roman commander
Publius Ventidius Bassus illustrate three general tactics used by the infantry to fight their mounted foes. These drew on Caesar's veteran legions and made Ventidius one of the Roman generals to celebrate a triumph against the Parthians. In three separate battles, he not only managed to defeat the Parthian armies and drive them out of the Roman territory but also managed to kill Parthia's three top military commanders during the battles. The adjustments of Ventidius were as follows: In his three victories over the horsemen, Ventidius had his infantry secure the high ground, bolstering defensive positions and manoeuvres with withering covering fire by the slingers. Seizure of hilly terrain features hindered sweeping enemy cavalry movements, obstructed avenues of attack and provided anchor points that allowed manoeuvring detachments to counter-attack, or to fall back if unfavourable conditions developed. Against the horsemen, heavy infantry units had to work closely with cavalry and light troops, and be mutually supporting, or they could be quickly isolated and destroyed. In one victory, Ventidius took a position on the high ground, and then dispatched a strong vanguard of cavalry against a Parthian concentration at the Syrian Gates, or narrow pass over Mount Amanus, leading from Cilicia into Syria. This vanguard was a decoy to lure the opposition forward. As the Parthians moved in for the kill, the Romans ambushed them from the flank with a detachment of slingers and infantry. Rather than wait for reinforcements by the allied force of Labenieus in the area, the Parthians decided to mount a full-scale attach on the main Roman position at dawn. Ventidius held back his forces until most of the Parthians were on the steep slope, then made a fast counter-attackhis infantry covered by the slingers. The Parthians were defeated in detail and Pharnapates the Parthian commander was killed.
Combined arms and quick advance in later eras. In the later Roman Empire, cavalry forces played a larger role, with the infantry in support. The campaign of the Emperor Julian against the Persians is instructive in this regard. On June 22, 363 a
large-scale clash occurred near the town of Maranga. Facing an enemy that threatened to blanket his troops with a hail of arrows, and in danger of envelopment, Julian deployed his force in a crescent formation, and ordered an advance by both infantry and cavalry on the double, thwarting both dangers by closing quickly. The gambit was successful. After a long battle, the Persians withdrewa tactical victory (albeit a costly one for the Romans according to some historians). The work of Roman historian
Ammianus Marcellinus offers a detailed description of the Persian campaign, including the quick charge by the heavy Roman infantry under Julian. :To prevent the preliminary volleys of the archers from disrupting our ranks he (Julian) advanced at the double and so ruined the effect of their fire... Roman foot in close order made a mighty push and drove the serried ranks of the enemy before them... Marcellinus's commentary also sharply contrasts the fighting spirit of the Persian infantrymen with those of Rome, stating that they had "aversion to pitched infantry battles". In an earlier engagement outside the walls of Ctesiphon, Marcellinus again notes the value of the quick advance by the infantry: :both sides fought hand-to-hand with spears and drawn swords; the quicker our men forced themselves into the enemy's line the less they were exposed to danger from arrows.
Mixed results against major cavalry enemies. Rome's overall record against the Parthians was favourable, although the
Parthian cavalry offered stiff resistance, as it was against the horsemen of Hannibal, and some Gallic opponents. Subsequent Roman leaders like Antony invaded Parthian territory but had to withdraw after severe losses. Others like emperors Severus and
Trajan saw great success in their invasions of Mesopotamia, defeating Parthian armies through combined arms tactics. Two of the major factors that have occupied scholars of the military will be discussed here: "barbarization" and the adaptation of a "mobile reserve" strategy. There are a number of controversies in this area with duelling scholars advancing competing theories.
"Barbarization" of the heavy infantry "Barbarization" is a common theme in many works on Rome (See
Gibbon,
Mommsen,
Delbrück, et al.), and thus cannot be excluded from any analysis of its infantry forces. Essentially it is argued that the increasing barbarization of the heavy legions weakened weaponry, training, morale and military effectiveness in the long run. The weapons changes described above are but one example. It could be argued that the use of barbarian personnel was nothing new. This is accurate, however, such use was clearly governed by "the Roman way". It was the barbarian personnel who had to adapt to Roman standards and organization, not the other way around. In the twilight of the Empire, this was not the case. Such practices as permitting the settlement of massive, armed barbarian populations on Roman territory, the watering down of the privilege of
Roman citizenship, increasing use of alien contingents, and relaxation or removal of traditionally thorough and severe Roman discipline, organization and control, contributed to the decline of the heavy infantry. The settlement of the
foederati, for example, saw large barbarian contingents ushered on to Roman territory, with their own organization, under their own leaders. Such groupings showed a tendency to neglect "the Roman way" in organization, training, logistics, etc., in favour of their own ideas, practices and agendas. These settlements may have bought short-term political peace for imperial elites, but their long-term effect was negative, weakening the traditional strengths of the heavy infantry in discipline, training and deployment. They also seemed to have lessened the incentive for remaining "Old Guard" troops to adhere to such strengths, since the barbarians received equal or more favour with less effort. Indeed, such "allied" barbarian contingents were at times to turn on the Romans, devastating wide areas with sack and pillage and even attacking imperial army formations. Other writers argue that while some ancient Romans did view the world in terms of barbarians versus civilized Romans (epitomized in
Hadrian's Wall of separation), the reality of Roman frontiers was a fuzzy set of interlocking zonespolitical, military, judicial and financial, rather than a neat linear boundary. Changes to the Roman forces that moved away from the old fighting organization order were thus the outcome of several influences, rather than simply the appearance of more uncivilized non-Romans.
Changes in the legions '', crossing the
Danube River, as depicted in a relief on the
Column of Marcus Aurelius in Rome To combat the more frequent raids and advances of their hostile neighbours the legions were changed from slow and heavy to much lighter troops, and cavalry was introduced as a serious concept. State-controlled factories produced vast quantities of less specialist arms such as
chain mail armour and spears as opposed to the
gladius and
lorica segmentata more prevalent in the early Empire. The difference between auxiliaries and legionaries began to become negligible from an equipment point of view. This meant that the new subdivided infantry lost the awesome power that the earlier legions had, meaning that whilst they were more likely to see a battle they were less likely to win it. That legion size was at an all-time low was also a factor. On the other hand, legions in the late Empire were used far more flexibly as accounts by authors like
Ammianus Marcellinus make clear. Smaller detachments waged more personal and smaller scale, yet intense operations against tribal foes on the Rhine and Danubian frontiers. Instead of vast formations of thousands of troops, smaller units would engage smaller-scale incursions by raiders.
Roman cavalry, while fast, were actually much too weak to cope with the very cavalry based invasions of the Huns, Goths, Vandals, and Sassanids. Their ineffectiveness was demonstrated at
Cannae and
Adrianople; in both instances, the cavalry was completely destroyed by a vastly more powerful enemy horse. Advances in Roman tactical thinking led to the adoption of eastern-style cataphracts and mass-use of auxiliary forces as cavalry, both of which were used to address previous shortcomings of the Roman army. The later Roman army was more cavalry-orientated than it had been before and as a result, detachments were able to be moved around the empire at will, ending the previous doctrine of keeping all forces on the frontiers at the edge of the Empire.
The mobile forces approach The "mobile reserve" strategy, traditionally identified with
Constantine the Great, saw a reversal of the traditional "forward" policy of strong frontier fortifications backed by legions stationed near likely zones of conflict. Instead, it is argued that the best troops were pulled back into a type of "mobile reserve" closer to the centre that could be deployed to trouble areas throughout the Empire. Some scholars claim this was a positive development, (Luttwak,
Delbruck, et al.) given growing difficulties with governing the vast empire, where political turmoil and severe financial difficulties had made the old preclusive security system untenable. Some writers such as Luttwak condemn the old-style "forward" policy as indicating a "
Maginot Line" mentality in the troubled latter centuries of the Empire.
Disadvantages of the mobile reserve strategy versus the "forward" policy Ancient writers like
Zosimus in the 5th century AD condemned the "reserve" policy as a major weakening of the military force. Other modern scholars (Ferrill et al.) also see the pullback as a strategic mistake, arguing that it left lower quality "second string"
limitanei forces to stop an enemy until the distant mobile reserve arrived. While the drop in quality did not happen immediately, it is argued that over time, the
limitanei declined into lightly armed, static watchman type troops that were of dubious value against increasing barbarian marauders on the frontiers. The pullback of the best infantry was based more on political reasons (shoring up the power bases of the emperors and various elites) rather than on military reality. In addition, it is claimed, the "forward" policy was not at all a static "Maginot" approach, but that traditional heavy legions and supporting cavalry could still move to a trouble spot by redeploying them from fortifications elsewhere along a particular frontier. Some scholars challenge the notion that a "mobile reserve" in the modern military sense existed in the Roman Empire, and instead argue that the shifts in an organization represent a series of field armies deployed in various areas as needed, particularly in the East. Others point to the heavy fiscal difficulties and political turmoil of the later Empire that made it difficult to continue a traditional policy.
Twilight of the hard-core infantry There are numerous other facets to the controversy, but whatever the school of thought, all agree that the traditional strengths and weaponry of the heavy infantry legion declined from the standards of earlier eras. The 4th-century writer
Vegetius, in one of the most influential Western military works
De re militari, highlighted this decline as the key factor in military weakness, noting that the core legions always fought as part of an integrated team of cavalry and light foot. In the latter years, this formula that had brought so much success petered out. Caught between the growth of lighter armed/less organized foot soldiers, and the increasing cavalry formations of the mobile forces, the "heavies" as the dominant force, withered on the vine. This does not mean that heavy units disappeared entirely, but that their mass recruitment, formation, organization and deployment as the dominant part of the Roman military was greatly reduced. Ironically, in Rome's final battles (the
Western Roman Empire) the defeats suffered were substantially inflicted by infantry forces (many fighting dismounted). Historian Arther Ferrill notes that even towards the end, some of the old infantry formations were still in use. Such grouping was increasingly ineffective, however, without the severe close order discipline, drill and organization of old times. In other cases, especially formidable units of enemy forces were invited to serve in the
Roman army as auxiliaries after peace was made. In the naval sphere, the Romans followed some of the same methods they used with the infantry, dropping their ineffective designs and copying, adapting and improving on Punic warships, and introducing heavier marine contingents (infantry fighters) on to their ships. • Roman organization was more flexible than those of many opponents. Compared to the tightly packed spearmen of the phalanx, the Roman heavy infantry, through their training and discipline, and operating in conjunction with light foot and cavalry, could quickly adopt a number of methods and formations depending on the situation. These range from the
tortoise formation during
siege warfare, to a hollow square against cavalry attack, to mixed units of heavy foot, horse and light infantry against guerrillas in Spain, to the classic "triple line" or checkerboard patterns. Against more sophisticated opponents the Romans also showed great flexibility at times, such as the brilliant adjustments Scipio made against Hannibal at Zama. These included leaving huge gaps in the ranks to trap the charging elephants, and the recall, reposition and consolidation of a single battle line that advanced to the final death struggle against the Carthaginian veterans of Italy. • Roman discipline, organization and logistical systemization sustained combat effectiveness over a longer period. Notably, the Roman system of
castra, or fortified camps, allowed the army to stay in the field on favourable ground and be rested and resupplied for battle. Well organized Roman logistics also sustained combat power, from routine resupply and storage to the construction of military roads, to state-run
arsenals and weapons factories, to well organized naval convoys that helped stave off defeat by
Carthage. The death of a leader generally did not cause the legions to lose heart in battle. Others stepped to the fore and carried on. In the defeat by Hannibal at the
River Trebia, 10,000 Romans cut their way through the debacle to safety, maintaining
unit cohesion when all around was rout, a testimony to their tactical organization and discipline. • The influence of the Roman military and civic culture, as embodied particularly in the heavy infantry legion, gave the Roman military consistent motivation and cohesion. Such culture included but was not limited to: (a) the valuing of
Roman citizenship, (b) the broad-based muster of free males into mass infantry units (as opposed to widespread use of foreign contingents, slaves or mercenaries), and (c) loyalty to those fighting units (the legion) which remained characteristically Roman in outlook and discipline. Citizenship conveyed certain valuable rights in Roman society, and was another element that helped to promote the standardization and integration of the infantry. The citizen under armsthe legion soldierwas supposed to reflect and practice the Roman ideal of
virtus, pietas, fides: self-discipline, respect and faithfulness to engagements. Implementation of such ideals could be mixed according to some writers, but it was "a trilogy driving every aspect of military, domestic, economic and social life". As such, it was a strong force for cohesion among Rome's infantrymen. ==See also==