by Horatius Piscinus on Sat Jun 26, 2004 12:51 pm
Salve Lupe
Yesterday I read through Caesar's account of the battle along with some other material, so now I can offer you a better opinion. Caesar had a good day.
Pharsalia
The main account we possess of the battle of Pharsalia comes from Caesar, which lacks several details. Other accounts by later authors provide some additional details, from which we can assume that other participants had left their own accounts. Even Caesar refers to events inside the camp of Pompeius that he learned after the battle. Still our knowledge of what happened that day is limited, and so some details have to be filled out by reasoned assumptions. Historians are not even agreed upon the exact location of the battlefield as Caesar provides no indication of where the battle was fought. Plutarch, Appian, Polyaenus and Suetonius placed the battle near Pharsalia. Hirtius, Frontius, Eutropius and Orosius claimed it was fought seven miles further west near Palaepharsalia. Both of these towns, however, lie south of the Enipeus River, where the battle was fought along its northern banks. From the accounts, Caesar had 22,000 men deployed in 80 cohorts, making up about seven legions. (Legiones IX and VIII had suffered so many casualties earlier that they were combined to form one unit smaller than a legion in size, and cohorts pulled from each legion formed another force comparable to an understrength legion.) He was supported by 1,000 cavalry. Pompeius had eleven legions of various quality, composed of 47,000 men in 110 cohorts, supported by a variety of cavalry units that came to roughly 10,000.
In spite of his numerical advantage, at Pharsalia Pompeius had certain disadvantages in the combat effectiveness of his individual legions and in his command structure. His tactical deployment can be criticized at several points, whereby he did not make full use of the advantages he held and even reduced the overall combat effectiveness of his overall army. To begin with, his legions were deployed in standard formation of ten men deep in three lines. On average his legions had a little more than 4,000, while Caesar had an average of a little under 4,000 men per legion. Because his units were already understrength, and because he had pulled out a cohort from each to form a special unit in reserve, Caesar's three lines were only six men deep. This worked to Caesar's advantage in two ways. First was the fact that in spite of his numerical inferiority, Caesar managed to form his legions into a line that was about the same length if not longer than that of Pompeius. About one Roman mile each. Pompeius had a clear advantage in cavalry, which he proposed to utilize by massing it on his left flank to sweep around Caesar's right. However he may have done better to try to use his numerical advantage to gain Caesar's flank, and this would also have supplied his cavalry with infantry support, which ultimately proved to be necessary.
The second advantage Caesar gained from his thinned lined is a little more difficult to explain. It involves the intangible of battlefield morale. We can contrast the potential battlefield morale of Caesar?s troops to those of Pompeius by considering a number of factors. First is that Caesar had a real advantage in the number of veteran units. Both armies had nearly the same number. Pompeius placed two veteran legions on his right, another two veteran legions on his left, with one veteran legion and some veteran Spanish cohorts in his center. These were separated by placing six less reliable units of new recruits between his three divisions. A problem that can occur in battle, especially in linear warfare such as the Romans fought, is that rear elements not directly engaged with the enemy may decide to run when things begin to look bad. The Roman tactical system compensated for this problem by placing its most experienced men of each legion in the third line, which was also its thinnest line. We do not really hear from Caesar how this may have influenced the battle, but I suspect that what happened is that when the veteran units on Pompeius' left were outflanked, the rear elements of the inexperienced legions between the left and center began to withdraw. This would have led to the front elements of the same legions then withdrawing as well, causing a chain reaction all along the Pompeian front. Caesar's seasoned legions, with thinner lines, probably was using their second line more frequently to relieve and support the front ranks. This meant that throughout the battle more of his men were actually engaged and had less time therefore to think about what was happening. Caesar?s third line were seasoned veterans and also older than the veterans Pompeius had. In this kind of warfare, as in 18th century warfare, seasoned professional in their late twenties to mid thirties tend to be more patient and sturdier in the face of an enemy. Even though a part of Caesar's line might suffer a temporary setback, the rear elements in other units were less likely to react by withdrawing. In addition Caesar had told these units prior to the battle that they were to await his command before advancing. In anticipation of his command, they were even less likely to withdraw and cause a general route as occurred with the Pompeian army.
Pompeius had deployed his army into its line formation before Caesar had ever left his camp. This allowed Caesar to consider his enemy's deployment, discern his plan and anticipate his maneuvers. Thus Caesar was able to deploy his army accordingly. Pompeius had a preponderance of cavalry. Placing all his cavalry on his left, along with all of his archers and slingers, made clear his intention. There was no doubt to the result as to what would happen with Caesar's cavalry when outnumbered 10 to 1. "Our cavalry failed to withstand their onslaught." Seeing the enemy's disposition from the start, Caesar had thus pulled a cohort from the third line of each legion to form a fourth line in support of his cavalry. This ad hoc unit of heavy infantry charged the Pompeian cavalry, not only pushing it back but also setting it to flight. This was to prove a decisive moment in the battle. How could a single line of roughly 1,600 infantry defeat an such overwhelming cavalry force? Caesar says that after defeating his own cavalry the Pompeian cavalry began to deploy in squadrons. This was probably an important detail, as Caesar's infantry was thereby able to attack each squadron separately. First it should be pointed out that cavalry attacking downhill as had Pompeius' is at a disadvantage. The nature of the horse is that it does better galloping uphill rather than downhill. This was a factor in the charge of the Heavy Brigade at Balaclava against a superior force of Russian cavalry. Also the distance that horses can charge is not very far, only about 2-300 meters. Even though the Pompeian cavalry had reached level ground before Caesar's infantry attacked, its horses were probably already in an exhausted state. Secondly cavalry units tend to become disrupted in a charge and after defeating the Caesarian cavalry would need to reorganize. By saying they began to deploy into squadrons, Caesar may indicate that the Pompeian cavalry was still in the process of sorting out their individual units when the infantry attacked. Thirdly cavalry of this era lacked an ability to make shock attacks as could heavy infantry, and it could not withstand the shock attack of heavy infantry. We have some idea of the various squadrons in the Pompeian cavalry - 600 Galatians, 500 Cappadicians, 500 Thracians, 200 Macedonians, 500 Gauls and Germans, 200 Syrian mounted archers, 800 of Pompeius' slaves and herdsmen, and then 3,400 Dardani, Bessi, Thessalians and others. Thus as Caesar's infantry came upon each squadron in turn, they actually had a numerical advantage as well as a tactical advantage. Caesar had thus managed, whether by design or by chance, to effect an economy of force with a massed force on a series of critical points of exhausted and disorganized enemy units, defeating them in detail. The infantry needed only to charge each squadron in turn, and before they even reached the cavalry, the squadron would turn in flight. Just as happened with the Russian cavalry at Balaclava, unit cohesion had transformed into a herd effect so that as soon as any of the cavalry in a squadron would turn, the entire unit turned. Some of these cavalry squadrons, like that of Pompeius' slaves, probably fled as soon as they saw their fellow cavalry squadrons put to flight. Thus the Caesarian infantry did not need to attack the Pompeian cavalry as a massed unit, taking on each squadron in turn, but the effect of its attack did affect the entire Pompeian cavalry as a single entity. This would seem to have been the case as Caesar said, "they all turned," almost as a single moment. With the cavalry dispersed from the field, Pompeius? archers and slingers, some 4,200 men, "unarmed and unprotected," were then massacred by Caesar's heavy infantry. This seems rather incredible; that such a large force could be trapped in such a way that they were all killed as Caesar claimed. But again, in this era, light infantry had little chance to stand against a concerted charge of heavy infantry, and probably they fled the field as well.
How both generals deployed their men stands in stark contrast. Pompeius had 2,000 beneficarii that he distributed throughout his line. The beneficarii were former soldiers recalled to duty and others in his command who had previously been rewarded for outstanding performance. They offered Pompeius a kind of cadre that could be used to hold his raw recruits together. We don?t know if that is in fact how he used them, only that we are told he dispersed them throughout the units in his line. Caesar instead appears to have used some task forcing during the battle. First, he formed his fourth line by withdrawing some of the better cohorts from each legion, concentrating them for a special assignment. Caesar also mentions Crastinus who was a recalled veteran, a beneficarius, "who the previous year had been chief centurion of Legio X, a man of outstanding valour." Crastinus led a party of 120 specially selected men in a crack unit that preceded Legio X into battle. We are not told exactly what their mission was. It was too small of a unit to act as a screening force for the legion, and not the kind of force that would perform such duty anyway. If their mission was to seize some position in preparation of the legion?s assault, we are not told what it was or why it was important. It is possible that they were sent as a spearhead that in spite of their few number could have disrupted the front rank of the opposing legion. Whatever their mission, we know that they succeeded and that Crastinus died in the effort. Crastinus is an example of Caesar task forcing, concentrating his better men into crack units for special assignments.
The most decisive factor in Caesar's victory, imho, came with Caesar's command and control over his army. Caesar had posted himself behind the center legions where he could watch the battle as it developed. Seeing his cavalry defeated, he gave the prearranged signal for his ad hoc infantry force to attack the Pompeian cavalry. Then when this force had gained Pompeius' left flank, Caesar gave another prearranged signal to his third line. At a critical moment the third line advanced on Pompeius' infantry line, pinning it in place so that it could not react to the attack on its left by sending reinforcements to counter Caesar?s maneuver. Caesar had retained command and control over his entire force, coordinating its movements into a single effort. In contrast Pompeius had a command structure that divided into several separate commands. Pompeius took personal command of the two legions on the left. Scipio had his own two Syrian legions in the center. Lentulus commanded the legions on the right and Labienus the cavalry force. No one had overall command of the six legions of raw recruits that were interspersed between these divisions, and thus each division was isolated from one another. Also by placing himself with his legions on the left, Pompeius had taken himself out of effective command of his entire army. No one was conducting the Pompeian army with an over all command at that point. Further the various divisions would unlikely have cooperated with one another on their own, since their commanders were in competition with one another over what offices they should receive after defeating Caesar. Both Scipio and Lentulus had laid claim to Caesar's office of pontifex maximus, and a bitter argument was held between them on the night before the battle. It was such bitter divisiveness between his subordinates in the first place that had forced Pompeius to abandon his strategy. Pompeius had been successfully out maneuvering Caesar, holding him in place by taking up defensive positions and forcing Caesar to then withdraw as his supplies ran low. This was exactly what Caesar had first set out to do that day, withdraw due to logistical problems. Pompeius decided instead to attack and finish Caesar through battle rather than attrition, and this decision can only have resulted from the problems he was facing within his own command. The effect on the Pompeian infantry line was thus the same as occurred with the Pompeian cavalry. The legions on Pompeius? left were taken in flank, and even before they were defeated Pompeius himself left the field. Likely, when the raw recruits between the left and center saw this, they began to flee. The other raw recruit legions between the center and right probably were the next to abandon the field. Their flanks thus exposed, engaged on their front, and Caesar?s legions now threatening their rear as well, Scipio at the center probably decided to turn, and with him the legions on the right under Lentulus. Each of Pompeius? divisions were essentially independent commands, left uncoordinated in their efforts through the lack of an over all commander. Caesar on the other hand retained unity of command over his army that allowed his legions to become mutually supporting and coordinate their attacks into a single effort.
Strategically Pompeius had performed better in the campaign that led up to Pharsalia. Whether he should have offered battle at this occasion was not strategically necessary. There were tactical flaws in his deployment of troops for the battle and in his plan of attack. Critical to the outcome was the flaw in Pompeius' divided command structure. Tactically Caesar performed much better at the battle itself. The result was not simply that Caesar had won and Pompeius had lost, and there was no simple cause for the result. There was a combination of factors, not all of which we can possibly know. What is clear is that both generals applied the basic principles of war, the one better than the other. Pompeius massed his cavalry, but not in a manner that adhered to the principle of an economy of force, did not task force his cavalry wing as he might have done and thereby failed to provide much needed support at the critical point to his plan. These failures were complicated further by the lack of command and control exercised by Pompeius. Caesar's army, although on the surface seemingly at a disadvantage numerically, was in fact the superior combat force. That was due to several factors, not least of which was the superior command structure of his individual units even below his centurions. Caesar capitalized on his advantages by proper application of several principles of war. Most important was Caesar's exercise of command and control over his entire command throughout the battle. The divided command of the Pompeian army led to its being defeated piecemeal, while unity of command allowed the Caesarian army to mass superior forces at critical points at critical moments in the engagement. Caesar's was a concerted effort against an ill organized and ill prepared foe, and the result was due more to Caesar's ability than to the failures of Pompeius.
M Horatius Piscinus
Sapere aude!