The Civil War
Prelude to Civil War
During his conquest of Gaul, Caesar had seen to it that his part of the Gallic loot was wisely spent in preserving and fortifying his position in Rome. His Populist acts as Praetor and Consul had severely alienated the middle group of senators and he needed to use Pompeius's connections with this group to legitimate his actions. However, the events of 52 BC make it clear that Cicero's efforts to estrange the two men had begun to bear fruit. Pompeius's legislation during his consulship in 52 BC was effectively targeted at Caesar -- A severe law against bribery at elections made retrospective to 70 BC; a law enforcing a five-year interval between tenure of magistracies in Rome and assumption of provincial commands, and one prohibiting candidature in absentia.
The crucial issue was whether or not there should be an interval between the date of Caesar's resignation of command in Gaul and the date on which he could enter a proposed second Consulship. If such an interval existed, Caesar would be a private citizen open to prosecution by his enemies and conviction would ruin him politically and might even cost him his life. This had been an issue at Lucca, in 56. Pompeius's reneging on the agreements of this meeting was either the acts of a weak and inept politician or calculated treachery to remove Caesar from power.
However, by 51 the question of having Caesar replaced was once again an issue in the Senatebut he survived by having the dangerous proposals vetoed by tribunes of the plebs who were firmly in his camp -- particularly Gaius Scribonius Curio in 50 and Mark Antony in 49. Despite being consul, Pompeius did little to prevent these attacks on Caesar and possibly even encouraged them. Retiring to his villa in Tarentum, Pompeius allowed the Optimates free reins in Rome.
It is highly unlikely that Caesar wished a civil war. In this respect, it is interesting to note the strong warning he makes in his report to the Senate for 52.
Indeed, for several days the soldiers had no grain at all and only managed to keep themselves from starving by driving in the cattle from distant villages. Yet one would not have heard a word from any of them that was unworthy of the greatness of Rome and of the victories they had won already. I used to go and speak to the men of each legion while they were working. I would tell them that, if they found their privations unbearable, I was quite ready to raise the siege; but one and all they would beg me not to do so. They had now, they said, served under me for many years without ever disgracing themselves or even failing to finish any task to which they had set their hands; they would count it as a disgrace if they were to abandon this siege they had begun; and they would rather undergo any hardship than fail to avenge the roman citizens who had been treacherously massacred by the Gauls at Cenabum. Messages to the same effect were given by the troops to their centurions and officers with the request that they should be passed on to me. (Caesar)
The message ought to be clear: Caesar had a loyal and battle-ready army behind him. Throughout 51-50, he attempted to negotiate with his enemies in Rome but without much success. The situation was brought to a head by the election of consuls in 50, Gaius Claudius Marcellus and Lucius Cornelius Lentulus, both firm anti-Caesarians. The Optimates succeeded in obtaining a senatorial resolution forcing Caesar to lay down his command at its terminal date. Curio then pushed through a resolution (by 370 votes to 22) that both Caesar and Pompeius should lay down their commands simultaneously on December 1, 50. The next day Marcellus (acting without authorization from the Senate or the People) offered the command over all troops in Italy to Pompeius, together with the power to raise more, and Pompeius accepted.
Caesar attempted a last compromise: On January 1, 49, the Senate received a letter from him proposing that he and Pompeius should lay down their commands simultaneously. Almost bitterly, Caesar recounts in the introduction to his account of the Civil War how his proposal is turned down. Soon after the decision is ratified, Pompeius is made Dictator and Caesar would be declared hostis, public enemy if he refused to lay down his command. It happened against the veto of the tribune of the plebs, but the time was no longer ripe for constitutional methods. If Caesar backed down he signed his death warrant, if he did not it remained to be seen who would die: Caesar, Pompeius or the Republic?
On January 10-11, Caesar, accompanied by half a Legion, stood beside the river Rubicon, the border between his province of Cisalpine Gaul and Italia. With the words:
"Iacta est alea" -- "Let the dice fly!"
he crossed into Italia. The civil war had begun.
Caesar in Italy
Neither Caesar, Pompeius nor even the greater part of the nobility were interested in a civil war. However, Caesar's success in building up political power made the champions of the old regime so implacably hostile that he was now faced with a choice between putting himself at his enemies' mercy or seizing the monopoly of power at which he was accused of aiming. Even as Caesar marched south towards Rome, continued efforts at negotiation were made. However Pompeius's growing jealousy of Caesar, and the antagonism of the Optimates made it impossible to find a solution to the problem.
Caesar tackled the problems facing him with his usual energy, weakening the position of his enemies in two ways. First and foremost he had to neutralize Pompeius who had supreme command of the senatorial forces and the only one capable of mustering serious resistance against Caesar. The other way his policy of clementia; Caesar had witnessed Sulla's proscriptions and had no intentions of repeating them. Through clemency, he hoped to receive the recognition of the broad senatorial class, as well as paving the way for the co-operation he knew would be necessary after the war. But there is no reason to presume that this clementia was purely political because all sources confirm that this friendly and accommodating manner was a part of his personality. It pained him when Cato, his most bitter enemy, committed suicide to escape his clementia and eighteen months later, after the battle of Pharsalos, he bitterly exclaimed
"Hoc voluerunt" -- "They wanted this."
The senate could muster only four legions in Italia, two of which were former legions of Caesar's to match the six with which Caesar brought into Italia. Pompeius's plan was to abandon Rome and Italy to Caesar and rely on his command of the sea and the resources of the East to starve out the Caesarians. He also had six veteran legions in Spain, that would threaten his rival's rear. But the Optimates, who saw him as the lesser of two evils where neither disciplined or co-operative, and Caesar advanced so swiftly down Italy that he barely succeeded in withdrawing to the Balkans.
Caesar in Spain
Realizing the danger posed by Pompeius's Spanish legions, Caesar took the best of his own troops across the Pyrenees, but despite their numerical superiority, the Pompeian commanders refused to risk a pitched battle. He therefore used his cavalry against them, cutting their supply lines. In forty days, despite unfavourable terrain and without a battle, he succeeded in subduing an army of greater size, led by experienced generals. Those troops who were willing, he enrolled in his own legions, the rest he disarmed and allowed to go free.
He then had himself appointed Dictator and conducted the Consular elections for 48 BC, which were won by himself and Publius Servilius Isauricus (son of the Isauricus under whom he had earlier served). He took the time to legislate an extension of citizenship to his beloved and loyal friends, the people of Cisalpine Gaul, regulated the finances, put more coins into circulation and assigned provincial governors. Then, resigning his Dictatorship, he marched to Brundisium to prepare for the final confrontation with Pompeius.
Caesar in Greece
Pompeius controlled the sea and had amassed in Greece an army of 11 Legions, 7000 cavalry and about 4000 auxiliaries. Unfortunately he was surrounded by friends and Consulars, who all thought they knew precisely what needed to be done. Most of them imagined that Caesar would soon be defeated, but rather than actively help in doing this, they spent their time discussing how to share the spoils. After much dithering, Cicero had finally decided to join Pompeius, but what he saw shocked him. Staying only long enough to toss about some sarcastic remarks, he withdrew his support.
Caesar, on the other hand, had none of these problems. With his characteristic swiftness, and despite only having enough transport for seven of his twelve legions, he crossed to Illyria in the very teeth of the enemy fleet. Once again he attempted to negotiate, but it is unlikely that anyone, least of all himself, now believed that a peaceful settlement was possible.
His situation was precarious however, until he received further reinforcements from Italy. With all his troops across, he attempted to encircle Pompeius, just as he had done with the Spanish legions. But an assault by the senatorial forces broke through his lines, and the ensuing battle resulted in Caesar's army suffering heavy losses. But despite his successes, Pompeius entirely failed to keep the initiative and Caesar therefore retreated into Thessaly to regroup.
Pompeius pursued, joining forces with the army of Metellus Scipio. Under pressure from the Optimates in his camp and emboldened by superior forces: 45,000 infantry and 7000 cavalry to Caesar's 22,000 infantry and 1000 cavalry, he opted to risk a pitched battle on the Plain of Pharsalos, a sensible decision had his opponent not been a commander of genius. Caesar accepted, placing a picked body of legionaries with his cavalry to redress the imbalance caused by Pompeius's superiority in cavalry. This unconventional tactic routed the cavalry of the enemy, and allowed his own infantry to outflank Pompeius, who fled the field, leaving his army to surrender.
Upon capturing the enemy camp, Caesar burnt Pompeius private papers -- an open gesture of conciliation. Perhaps too, this was the only way in which he could express his regret that most of 15,000 dead were Roman citizens. He then set out in pursuit of Pompeius.