The Parthians were, just like Crassus formerly, in no haste to attack, but during the years 701 and 702 sent only weak flying bands, who were easily repulsed, across the Euphrates; so that Cassius obtained time to reorganize the army in some measure, and with the help of the faithful adherent of the Romans, Herodes Antipater, to reduce to obedience the Jews, whom resentment at the spoliation of the temple perpetrated by Crassus had already driven to arms. The Roman government would thus have had full time to send fresh troops for the defence of the threatened frontier; but this was left undone amidst the convulsions of the incipient revolution, and, when at length in 703 the great Parthian invading army appeared on the Euphrates, Cassius had still nothing to oppose to it but the two weak legions formed from the remains of the army of Crassus.
Of course with these he could neither prevent the crossing nor defend the province. Syria was overrun by the Parthians, and all Western Asia trembled. But the Parthians did not understand the besieging of towns. They not only retreated from Antioch, into which Cassius had thrown himself with his troops, without having accomplished their object, but they were on their retreat along the Orontes allured into an ambush by Cassius' cavalry and there severely handled by the Roman infantry; prince Osaces was himself among the slain. Friend and foe thus perceived that the Parthian army under an ordinary general and on ordinary ground was not capable of much more than any other Oriental army. However, the attack was not abandoned. Still during the winter of 703-704 Pacorus lay encamped in Cyrrhestica on this side of the Euphrates; and the new governor of Syria, Marcus Bibulus, as wretched a general as he was an incapable statesman, knew no better course of action than to shut himself up in his fortresses. It was generally expected that the war would break out in 704 with renewed fury. But instead of turning his arms against the Romans, Pacorus turned against his own father, and accordingly even entered into an understanding with the Roman governor. Thus the stain was not wiped from the shield of Roman honour, nor was the reputation of Rome restored in the east; but the Parthian invasion of Western Asia was over, and the Euphrates boundary was, for the time being at least, retained.
In Rome meanwhile the periodical volcano of revolution was whirling upward its clouds of stupefying smoke. The Romans began to have no longer a soldier or a denarius to be employed against the public foe - no longer a thought for the destinies of the nations. It is one of the most dreadful signs of the times, that the huge national disaster of Carrhae and Sinnaca gave the politicians of that time far less to think and speak of than that wretched tumult on the Appian road, in which, a couple of months after Crassus, Clodius the partisan-leader perished; but it is easily conceivable and almost excusable. The breach between the two regents, long felt as inevitable and often announced as near, was now assuming such a shape that it could not be arrested. Like the boat of the ancient Greek mariners' tale, the vessel of the Roman community now found itself as it were between two rocks swimming towards each other; expecting every moment the crash of collision, those whom it was bearing, tortured by nameless anguish, into the eddying surge that rose higher and higher were benumbed; and, while every slightest movement there attracted a thousand, eyes, no one ventured to give a glance to the right or the left.
After Caesar had, at the conference of Luca in April 698, agreed to considerable concessions as regarded Pompeius, and the regents had thus placed themselves substantially on a level, their relation was not without the outward conditions of durability, so far as a division of the monarchical power - in itself indivisible - could be lasting at all. It was a different question whether the regents, at least for the present, were determined to keep together and mutually to acknowledge without reserve their title to rank as equals. That this was the case with Caesar, in so far as he had acquired the interval necessary for the conquest of Gaul at the price of equalization with Pompeius, has been already set forth.
But Pompeius was hardly ever, even provisionally, in earnest with the collegiate scheme. His was one of those petty and mean natures, towards which it is dangerous to practise magnanimity; to his paltry spirit it appeared certainly a dictate of prudence to supplant at the first opportunity his reluctantly acknowledged rival, and his mean soul thirsted after a possibility of retaliating on Caesar for the humiliation which he had suffered through Caesar's indulgence. But while it is probable that Pompeius in accordance with his dull and sluggish nature never properly consented to let Caesar hold a position of equality by his side, yet the design of breaking up the alliance doubtless came only by degrees to be distinctly entertained by him. At any rate the public, which usually saw better through the views and intentions of Pompeius than he did himself, could not be mistaken in thinking that at least with the death of the beautiful Julia - who died in the bloom of womanhood in the autumn of 700 and was soon followed by her only child to the tomb - the personal relation between her father and her husband was broken up. Caesar attempted to re-establish the ties of affinity which fate had severed; he asked for himself the hand of the only daughter of Pompeius, and offered Octavia, his sister's grand-daughter, who was now his nearest relative, in marriage to his fellow-regent; but Pompeius left his daughter to her existing husband Faustus Sulla the son of the regent, and he himself married the daughter of Quintus Metellus Scipio. The personal breach had unmistakeably begun, and it was Pompeius who drew back his hand. It was expected that a political breach would at once follow; but in this people were mistaken; in public affairs a collegiate understanding continued for a time to subsist. The reason was, that Caesar did not wish publicly to dissolve the relation before the subjugation of Gaul was accomplished, and Pompeius did not wish to dissolve it before the governing authorities and Italy should be wholly reduced under his power by his investiture with the dictatorship.
It is singular, but yet readily admits of explanation, that the regents under these circumstances supported each other; Pompeius after the disaster of Aduatuca in the winter of 700 handed over one of his Italian legions that were dismissed on furlough by way of loan to Caesar; on the other hand Caesar granted his consent and his moral support to Pompeius in the repressive measures which the latter took against the stubborn republican opposition.
It was only after Pompeius had in this way procured for himself at the beginning of 702 the undivided consulship and an influence in the capital thoroughly outweighing that of Caesar, and after all the men capable of arms in Italy had tendered their military oath to himself personally and in his name, that he formed the resolution to break as soon as possible formally with Caesar; and the design became distinctly enough apparent. That the judicial prosecution which took place after the tumult on the Appian Way lighted with unsparing severity precisely on the old democratic partisans of Caesar[12], might perhaps pass as a mere awkwardness. That the new law against electioneering intrigues, which had retrospective effect as far as 684, included also the dubious proceedings at Caesar's candidature for the consulship[13], might likewise be nothing more, although not a few Caesarians thought that they perceived in it a definite design. But people could no longer shut their eyes, however willing they might be to do so, when Pompeius did not select for his colleague in the consulship his former father-in-law Caesar, as was fitting in the circumstances of the case and was in many quarters demanded, but associated with himself a puppet wholly dependent on him in his new father-in-law Scipio[14]; and still less, when Pompeius at the same time got the governorship of the two Spains continued to him for five years more, that is to 709, and a considerable fixed sum appropriated from the state-chest for the payment of his troops, not only without stipulating for a like prolongation of command and a like grant of money to Caesar, but even while labouring ulteriorly to effect the recall of Caesar before the term formerly agreed on through the new regulations which were issued at the same time regarding the holding of the governorships.