Under these circumstances the war opened at the beginning of January 705. Of troops capable of marching Caesar had not more than a legion - 5000 infantry and 300 cavalry - at Ravenna, which was by the highway some 240 miles distant from Rome; Pompeius had two weak legions - 7000 infantry and a small squadron of cavalry - under the orders of Appius Claudius at Luceria, from which, likewise by the highway, the distance was just about as great to the capital. The other troops of Caesar, leaving out of account the raw divisions of recruits still in course of formation, were stationed, one half on the Saone and Loire, the other half in Belgica, while Pompeius' Italian reserves were already arriving from all sides at their rendezvous; long before even the first of the Transalpine divisions of Caesar could arrive in Italy, a far superior army could not but be ready to receive it there. It seemed folly, with a band of the strength of that of Catilina and for the moment without any effective reserve, to assume the aggressive against a superior and hourly-increasing army under an able general; but it was a folly in the spirit of Hannibal. If the beginning of the struggle were postponed till spring, the Spanish troops of Pompeius would assume the offensive in Transalpine, and his Italian troops in Cisalpine, Gaul, and Pompeius, a match for Caesar in tactics and superior to him in experience, was a formidable antagonist in such a campaign running its regular course. Now perhaps, accustomed as he was to operate slowly and surely with superior masses, he might be disconcerted by a wholly improvised attack; and that which could not greatly discompose Caesar's thirteenth legion after the severe trial of the Gallic surprise and the January campaign in the land of the Bellovaci[14], - the suddenness of the war and the toil of a winter campaign - could not but disorganize the Pompeian corps consisting of old soldiers of Caesar or of ill-trained recruits, and still only in the course of formation.
Accordingly Caesar advanced into Italy[15]. Two highways led at that time from the Romagna to the south; the Aemilio-Cassian which led from Bononia over the Apennines to Arretium and Rome, and the Popillio-Flaminian, which led from Ravenna along the coast of the Adriatic to Fanum and was there divided, one branch running westward through the Furlo pass to Rome, another southward to Ancona and thence onward to Apulia. On the former Marcus Antonius advanced as far as Arretium, on the second Caesar himself pushed forward. Resistance was nowhere encountered; the recruiting officers of quality had no military skill, their bands of recruits were no soldiers, the inhabitants of the country towns were only anxious not to be involved in a siege. When Curio with 1500 men approached Iguvium, where a couple of thousand Umbrian recruits had assembled under the praetor Quintus Minucius Thermus, general and soldiers took to flight at the bare tidings of his approach; and similar results on a small scale everywhere ensued.
Caesar had to choose whether he would march against Rome, from which his cavalry at Arretium were already only about 130 miles distant, or against the legions encamped at Luceria. He chose the latter plan. The consternation of the opposite party was boundless. Pompeius received the news of Caesar's advance at Rome; he seemed at first disposed to defend the capital, but, when the tidings arrived of Caesar's entrance into the Picenian territory and of his first successes there, he abandoned Rome and ordered its evacuation. A panic, augmented by the false report that Caesar's cavalry had appeared before the gates, came over the world of quality. The senators, who had been informed that every one who should remain behind in the capital would be treated as an accomplice of the rebel Caesar, flocked in crowds out at the gates. The consuls themselves had so totally lost their senses, that they did not even secure the treasure; when Pompeius called upon them to fetch it, for which there was sufficient time, they returned the reply that they would deem it safer, if he should first occupy Picenum. All was perplexity; consequently a great council of war was held in Teanum Sidicinum (23 Jan.), at which Pompeius, Labienus, and both consuls were present. First of all proposals of accommodation from Caesar were again submitted; even now he declared himself ready at once to dismiss his army, to hand over his provinces to the successors nominated, and to become a candidate in the regular way for the consulship, provided that Pompeius were to depart for Spain, and Italy were to be disarmed.
The answer was, that if Caesar would immediately return to his province, they would bind themselves to procure the disarming of Italy and the departure of Pompeius by a decree of the senate to be passed in due form in the capital; perhaps this reply was intended not as a bare artifice to deceive, but as an acceptance of the proposal of compromise; it was, however, in reality the opposite. The personal conference which Caesar desired with Pompeius the latter declined, and could not but decline, that he might not by the semblance of a new coalition with Caesar provoke still more the distrust already felt by the constitutional party. Concerning the management of the war it was agreed in Teanum, that Pompeius should take the command of the troops stationed at Luceria, on which notwithstanding their untrustworthiness all hope depended; that he should advance with these into his own and Labienus' native country, Picenum; that he should personally call the general levy there to arms, as he had done some thirty-five years ago[16], and should attempt at the head of the faithful Picentine cohorts and the veterans formerly under Caesar to set a limit to the advance of the enemy.
Everything depended on whether Picenum would hold out until Pompeius should come up to its defence. Already Caesar with his reunited army had penetrated into it along the coast road by way of Ancona. Here too the preparations were in full course; in the very northernmost Picenian town Auximum a considerable band of recruits was collected under Publius Attius Varus; but at the entreaty of the municipality Varus evacuated the town even before Caesar appeared, and a handful of Caesar's soldiers which overtook the troop not far from Auximum totally dispersed it after a brief conflict - the first in this war. In like manner soon afterwards Gaius Lucilius Hirrus with 3000 men evacuated Camerinum, and Publius Lentulus Spinther with 5000 Asculum. The men, thoroughly devoted to Pompeius, willingly for the most part abandoned their houses and farms, and followed their leaders over the frontier; but the district itself was already lost, when the officer sent by Pompeius for the temporary conduct of the defence, Lucius Vibullius Rufus - no genteel senator, but a soldier experienced in war - arrived there; he had to content himself with taking the six or seven thousand recruits who were saved away from the incapable recruiting officers, and conducting them for the time to the nearest rendezvous.
This was Corfinium, the place of meeting for the levies in the Albensian, Marsian and Paelignian territories; the body of recruits here assembled, of nearly 15,000 men, was the contingent of the most warlike and trustworthy regions of Italy, and the flower of the army in course of formation for the constitutional party. When Vibullius arrived here, Caesar was still several days' march behind; there was nothing to prevent him from immediately starting agreeably to Pompeius' instructions and conducting the saved Picenian recruits along with those assembled at Corfinium to join the main army in Apulia. But the commandant in Corfinium was the designated successor to Caesar in the governorship of Transalpine Gaul, Lucius Domitius, one of the most narrow-minded and stubborn of the Roman aristocracy; and he not only refused to comply with the orders of Pompeius, but also prevented Vibullius from departing at least with the men from Picenum for Apulia. So firmly was he persuaded that Pompeius only delayed from obstinacy and must necessarily come up to his relief, that he scarcely made any serious preparations for a siege and did not even gather into Corfinium the bands of recruits placed in the surrounding towns. Pompeius however did not appear, and for good reasons; for, while he might perhaps apply his two untrustworthy legions as a reserved support for the Picenian general levy, he could not with them alone offer battle to Caesar.
Instead of him after a few days Caesar came (14 Feb.). His troops had been joined in Picenum by the twelfth, and before Corfinium by the eighth, legion from beyond the Alps, and, besides these, three new legions had been formed partly from the Pompeian men that were taken prisoners or presented themselves voluntarily,
