But, although the republicans were still stirring and were even refreshed by an isolated success here and there, chiefly through the blunders of Pompeius, the object which the regents had proposed to themselves in that dictatorship was on the whole attained, the reins were drawn tighter, the republican party was humbled, and the new monarchy was strengthened. The public began to reconcile themselves to the latter. When Pompeius not long after recovered from a serious illness, his restoration was celebrated throughout Italy with the accompanying demonstrations of joy which are usual on such occasions in monarchies. The regents showed themselves satisfied; as early as the 1st of August 702 Pompeius resigned his dictatorship, and shared the consulship with his client Metellus Scipio.

Marcus Crassus had for years been reckoned among the heads of the "three-headed monster" without any proper title to be so included. He served as a makeweight to trim the balance between the real regents Pompeius and Caesar, or, to speak more accurately, his weight fell into the scale of Caesar against Pompeius. This part is not a too reputable one; but Crassus was never hindered by any keen sense of honour from pursuing his own advantage. He was a merchant and was open to be dealt with. What was offered to him was not much; but, when more was not to be got, he accepted it, and sought to forget the ambition that fretted him, and his chagrin at occupying a position so near to power and yet so powerless, amidst his always accumulating piles of gold. But the conference at Luca changed the state of matters also for him; with the view of still retaining the preponderance as compared with Pompeius after concessions so extensive, Caesar gave to his old confederate Crassus an opportunity of attaining in Syria through the Parthian war the same position to which Caesar had attained by the Celtic war in Gaul. It was difficult to say whether these new prospects proved more attractive to the ardent thirst for gold which had now become at the age of sixty a second nature and grew only the more intense with every newly-won million, or to the ambition which had been long repressed with difficulty in the old man's breast and now glowed in it with restless fire. He arrived in Syria as early as the beginning of 700; he had not even waited for the expiry of his consulship to depart. Full of impatient ardour he seemed desirous to redeem every minute with the view of making up for what he had lost, of gathering in the treasures of the east in addition to those of the west, of achieving the power and glory of a general as rapidly as Caesar, and with as little trouble as Pompeius.

He found the Parthian war already commenced. The faithless conduct of Pompeius towards the Parthians has been already mentioned[1]; he had not respected the stipulated frontier of the Euphrates and had wrested several provinces from the Parthian empire for the benefit of Armenia, which was now a client state of Rome. King Phraates had submitted to this treatment; but after he had been murdered by his two sons Mithradates and Orodes, the new king Mithradates immediately declared war on the king of Armenia, Artavasdes, son of the recently deceased Tigranes (about 698)[2]. This was at the same time a declaration of war against Rome; therefore as soon as the revolt of the Jews was suppressed, Gabinius, the able and spirited governor of Syria, led the legions over the Euphrates. Meanwhile, however, a revolution had occurred in the Parthian empire; the grandees of the kingdom, with the young, bold, and talented grand vizier at their head, had overthrown king Mithradates and placed his brother Orodes on the throne. Mithradates therefore made common cause with the Romans and resorted to the camp of Gabinius. Everything promised the best results to the enterprise of the Roman governor, when he unexpectedly received orders to conduct the king of Egypt back by force of arms to Alexandria[3]. He was obliged to obey; but, in the expectation of soon coming back, he induced the dethroned Parthian prince who solicited aid from him to commence the war in the meanwhile at his own hand. Mithradates did so; and Seleucia and Babylon declared for him; but the vizier captured Seleucia by assault, having been in person the first to mount the battlements, and in Babylon Mithradates himself was forced by famine to surrender, whereupon he was by his brother's orders put to death.

His death was a palpable loss to the Romans; but it by no means put an end to the ferment in the Parthian empire, and the Armenian war continued. Gabinius, after ending the Egyptian campaign, was just on the eve of turning to account the still favourable opportunity and resuming the interrupted Parthian war, when Crassus arrived in Syria and along with the command took up also the plans of his predecessor. Full of high-flown hopes he estimated the difficulties of the march as slight, and the power of resistance in the armies of the enemy as yet slighter; he not only spoke confidently of the subjugation of the Parthians, but was already in imagination the conqueror of the kingdoms of Bactria and India.

The new Alexander, however, was in no haste. Before he carried into effect these great plans, he found leisure for very tedious and very lucrative collateral transactions. The temples of Derceto at Hierapolis Bambyce and of Jehovah at Jerusalem and other rich shrines of the Syrian province, were by order of Crassus despoiled of their treasures; and contingents or, still better, sums of money instead were levied from all the subjects. The military operations of the first summer were limited to an extensive reconnaissance in Mesopotamia; the Euphrates was crossed, the Parthian satrap was defeated at Ichnae (on the Belik to the north of Rakkah), and the neighbouring towns, including the considerable one of Nicephorium (Rakkah), were occupied, after which the Romans having left garrisons behind in them returned to Syria. They had hitherto been in doubt whether it was more advisable to march to Parthia by the circuitous route of Armenia or by the direct route through the Mesopotamian desert. The first route, leading through mountainous regions under the control of trustworthy allies, commended itself by its greater safety; king Artavasdes came in person to the Roman headquarters to advocate this plan of the campaign. But that reconnaissance decided in favour of the march through Mesopotamia. The numerous and flourishing Greek and half-Greek towns in the regions along the Euphrates and Tigris, above all the great city of Seleucia, were altogether averse to the Parthian rule; all the Greek townships with which the Romans came into contact had now, like the citizens of Carrhae at an earlier time[4], practically shown how ready they were to shake off the intolerable foreign yoke and to receive the Romans as deliverers, almost as countrymen.

The Arab prince Abgarus, who commanded the desert of Edessa and Carrhae and thereby the usual route from the Euphrates to the Tigris, had arrived in the camp of the Romans to assure them in person of his devotedness. The Parthians had appeared to be wholly unprepared.