Tactician

Battle was where Caesar most clearly demonstrated his particular brand of military genius. He was a master tactician. If his strategic thinking was largely conventional - albeit boldly and swiftly executed - once combat was in the offing Caesar could display an inventiveness and extraordinary sureness of touch that set him apart from his peers. Pharsalus can stand as one striking example among many. In August of 47 after several times declining Caesar’s offers of battle, Pompey at last decided that it was time to move in for the kill. He commanded 11 legions to Caesar’s eight, but since his troops would be no match for Caesar’s veteran legionaries, he placed his chief hope for victory in his far more numerous cavalry, 6,400 to Caesar’s 1,000. Massing them on his left flank and supporting them with light infantry, Pompey intended their charge to drive off Caesar’s horse. Pompey’s cavalry would then swing around behind Caesar’s line of infantry and attack them from the rear while his own infantry held Caesar’s legions in place until the trap could be sprung. This plan of attack had venerable roots stretching back to Hannibal’s victory at Cannae and even earlier to the battles of Alexander the Great against Persia. It ought to have worked, and against a lesser general it would have. But Caesar’s tactical abilities were more than equal to this challenge. As the two sides deployed and Caesar watched Pompey’s cavalry mass against his own, he understood immediately the threat they posed not only to his cavalry but to his infantry. To meet it, Caesar improvised. A Roman legion in this period was organized in ten cohorts of about 500 men each. In combat, each legion’s cohorts were usually marshaled in three lines of three or four cohorts each, one behind the other, and the legions in this formation lined up next to each another. Caesar therefore ordered one cohort from the third line of each of his eight legions to fall out, march to the right flank, and form a fourth line behind and at an oblique angle to the Tenth Legion, which held the end of the right wing. Thus prepared, he gave the signal to advance. Everything fell out as Caesar had foreseen. Pompey’s cavalry drove off Caesar’s horsemen and then attacked the legions on Caesar’s right. At that point, Caesar ordered his fourth line, held in reserve until then, to attack Pompey’s cavalry. They charged so vigorously that they put them to headlong flight. With the protection of their cavalry gone, Pompey’s light infantry were no match for Caesar’s heavily armed legionaries, and they were slaughtered. That accomplished, Caesar’s fourth line was free to attack Pompey’s legions in the flank and rear. The result was a rout: Pompey’s legions fled, along with Pompey himself and the rest of his officers (BC 3.88-99).

It is worth dwelling on this battle at some length because it strikingly illustrates just what sets Caesar so much apart from other generals: his ability not simply to grasp what the enemy intended but to improvise a brilliant counter-stroke to meet it. Pompey’s tactic at Pharsalus is often termed ‘‘hammer and anvil,’’ in that the infantry, the ‘‘anvil,’’ holds the enemy infantry in place, while the ‘‘hammer,’’ the cavalry, swings around the rear and strikes it from behind. It had never, to our knowledge, been effectively countered - until Pharsalus. And Caesar’s achievement in doing so is all the more impressive because it went against the grain of almost the entire history of Roman tactical doctrine to that point. One of the keys to Rome’s unparalleled record of battlefield successes had always been the independent maneuverability of the cohorts and earlier the maniples of which their legions had been composed. This feature had allowed generals to move maniples and cohorts back from direct contact with the enemy as they became exhausted or overwhelmed and to move fresh units forward to take their places. But almost never do we find generals going beyond this in open field battles to exploit the vastly greater range of tactical options that the ability of these units to maneuver independently allowed. At Pharsalus Caesar did, and it won him the day.

However, Caesar’s genius at tactical improvisation would have gone for naught without superbly trained soldiers to execute his orders. It is worth stressing that Caesar’s orders for cohorts to fall out of the third line and march to the right required them to carry out a highly unusual maneuver, and just the sort of unexpected change in long-standing tactical practice that could lead to confusion and disaster, especially at a moment as fraught with tension as that just before a battle began. That the maneuver did not fail but was carried out smoothly and rapidly is testament to the exceptionally high state of training and discipline among the men Caesar commanded. For if Caesar was a virtuoso on the battlefield, the instrument he performed on was one fully capable of meeting his standard of performance. In part Caesar’s success at Pharsalus can be chalked up to the fact that centuries of warfare had brought the Roman army to the apogee of its development.

Roman soldiers in this period were not, as sometimes claimed, professionals. They were citizen-soldiers, conscripted from Italy’s small farms. The men served for ten years or more before they returned to the land to marry and begin families. The lengthy periods that Roman legionaries could be kept at war - all year round for years at a time - allowed them to develop a skill at soldiering, a degree of discipline and a depth of experience, and a familiarity and trust in one another that could sustain them through the rigors of long, difficult campaigns as well as in the crucible of combat (Rosenstein 2004: 29-31). Ten years’ fighting in Gaul had brought Caesar’s legions to a point where they could not only execute flawlessly a new and unexpected maneuver, but even direct themselves in battle. When Caesar gave the order to charge at Pharsalus, his men began to advance rapidly, ready to hurl their pila. But when they saw Pompey’s legions remaining in place, as Pompey had ordered, to await their charge, they feared that they would reach their opponents exhausted and disordered. Caesar’s legions then of their own accord halted, dressed their lines, and resumed their advance. Only when they came within missile range did they hurl their pila and charge (BC 3.92-3). Faced with the furious onslaught of these highly trained, disciplined, and battle-hardened troops, Pompey’s forces did not stand a chance, even had Caesar’s fourth line not attacked them from the rear.

Caesar’s battlefield virtuosity developed over long years and many campaigns.2 His first battles against the Helvetii reveal clearly how far he was from tactical mastery at that point. At Bibractae, where he faced the main body of their forces, he elected to await their charge at the top of a hill, only pursuing when the enemy’s ranks had been broken, much as his great-uncle Marius had done half a century earlier at Aquae Sextiae. Yet his army nearly came to grief when they were surprised in their pursuit by the sudden arrival of the Helvetian rearguard behind the Romans. At their appearance Caesar found himself trapped between two enemies. While his third line of cohorts faced about to confront this new threat, the first and second continued the attack against the main body of the enemy, who, given fresh heart by the reinforcements, renewed the fight with great vigor. The battle raged long and hard, and although the Romans ultimately triumphed, their losses were heavy. Caesar had to spend three days tending to the wounded and burying his dead (BG 1.23-6). Caesar had surrendered the tactical initiative by allowing the enemy’s actions to dictate how the battle unfolded, and in so doing he had come very close to defeat. He would never make the same mistake again. Against Ariovistus a few months later, Caesar seized the initiative, forcing battle on his terms despite the Germans’ initial reluctance to come out and fight (BG 1.50-1).

More important is the fact that Caesar soon after this began to embrace what might be termed a tactical template developed initially by Sulla and refined subsequently by two of Sulla’s lieutenants, Lucullus and Pompey. This template entailed taking control of the field of battle by altering its contours through fortifications, fortified camps, and entrenchments. In 57, at his initial encounter with the Belgae, Caesar used well-defended earthworks and a fortified camp to neutralize his opponents’ superiority in numbers (BG 2.9). Caesar and his subordinates repeatedly altered the military topography in order to gain a tactical advantage in their conquest of Gaul and in the battles during the civil war that followed. His most masterful employment of this technique was unquestionably at Alesia, the climactic battle of the Gallic revolt. Here Caesar surrounded the Gallic stronghold with a highly elaborate and very strong double-walled fortification and presented its defenders with a stark choice between attacking those fortifications and starvation. Thereby he forced not only the besieged, but the relief force sent to break the siege, to fight on his terms, enabling his outnumbered legionaries nonetheless to prevail (BG 7.60-89).

At Alesia, too, another ingredient in Caesar’s battlefield generalship emerges forcefully. He possessed enormous personal courage, and repeatedly displayed a readiness to share the dangers of combat with his men, especially in crises (cf. Suet. lul. 62; Plut. Caes. 17.2). His appearance spurred his men to fight even more fiercely until they prevailed, and in ancient battles that sort of determination and ferocity often made the critical difference between victory and defeat. At the climax of the battle at Alesia, when an attack by the Gallic relief forces was on the verge of capturing a key fort, threatening to compromise fatally Caesar’s defenses and break the siege, Caesar sent in his reserves and then went himself to the scene of the action with more troops. Both sides recognized him. His men redoubled their efforts and finally put the enemy to flight (BG 7.87-8). More than once, his soldiers’ awareness that the eyes of their commander were upon them steadied them, increased their resolve, and fired their ardor. By far the most striking instance came in 57, at the Sambre River, where the Belgae’s ambush surprised the legions at the end of their day’s march as they were making camp. The legionaries struggled to arm themselves and form ranks, aided by their experience and training and the presence of their officers. However, on the right, Caesar noticed that the men of the Twelfth Legion were bunched together. Most of the centurions had been killed or wounded, and the whole formation was in danger of collapse. Caesar seized a shield from one of the men in the rear ranks and then, as he writes, ‘‘he [Caesar] advanced into the front ranks, and calling on the centurions by name and encouraging the rest of the soldiers, he ordered them to advance and open up their ranks so that they could use their swords more easily. His arrival brought hope and renewed their courage since each soldier strives to do his best in the sight of his commander no matter how desperate his situation’’ (BG 2.25).

In part, Caesar’s willingness to expose himself to danger was conventional. Roman generals were expected to display bravery and steadfast determination, especially when defeat loomed, precisely because any general’s presence incited their men to do their utmost (Rosenstein 1990: 114-52). And generals needed to be close to the action in order to control the movements of their forces as the battle progressed (Goldsworthy 1998: 206-10). However, as we have seen, Caesar’s personal courage is evident at the very outset of his military career in his winning of the corona civica for exceptional bravery in battle. His readiness to enter the thick of the fray when necessary was simply one aspect of his unwillingness to spare himself or to observe any limits in the pursuit of the goals he had set himself. The same ambition that drove him to do anything and everything for the friends whose help he hoped would be the foundation of his political success (Sall. Cat. 54.4) also impelled him to endure unflinchingly whatever hardships presented themselves on campaign. This willingness to share their toils endeared him to his men and forged a powerful bond between the soldiers and their general that was another of the keys to Caesar’s military success (Suet. lul. 57; Plut. Caes. 17.1-3). That bond Caesar strengthened through the lavish rewards he bestowed upon his men following their victories and at times a permissiveness that struck traditionalists as un-Roman and corrosive of their fighting spirit: Caesar was wont to boast that his soldiers could fight well even drenched with perfume (BG2.33; Suet. lul. 67.1-2). Yet he expected instant obedience to his orders and iron discipline when necessary, and he got both time and again (Suet. lul. 65). He was devoted to his men, and they responded in kind (Suet. lul. 67.1-70). The steadfast loyalty of his legions and their determination not to fall short in his estimation placed in Caesar’s hands as formidable a military instrument as any Roman general - or any other general for that matter - ever wielded.