It had been arranged between Caesar and Pompey, that during the absence of the former in Gaul, the latter should act with the popular party, and keep the nobility in the condition of impotence to which it had been reduced in the consulship of Caesar. Partly from jealousy of Caesar, partly from sheer incapacity, Pompey, after much vacillation and duplicity, finally allied himself with the nobles, thinking with their aid to crush his rival and thereafter to be supreme. The nobles, for their part, thought they would know how to deal with Pompey if once Caesar was out of the way. In the negotiations which preceded the civil war, Caesar showed a moderation and fairness in striking contrast with the unscrupulous and headstrong violence of the nobles, who had not even formal legality on their side. But when he was finally summoned to hand over his province and army to a nominee of the Senate, on pain of being declared a public enemy, and when the tribunes who had reversed the resolution of the Senate were obliged to fly for their lives to his camp, he suddenly crossed the river Rubicon, the boundary of his province, and marched on Rome (B.C. 49). He had but one legion with him; the bulk of his army was far away in its Gallic cantonments. The forces of Pompey were overwhelmingly superior in numbers. But the rapid and daring advance of Caesar prevented their concentration. He came, not merely the adored general of a veteran army, but the long-tried and consistent leader of the liberal party, who had never swerved from his principles, never betrayed his friends, never flinched from dangers. Fascinated by his success and encouraged by his clemency, towns everywhere opened their gates and Pompeian levies joined him, swelling his army at every stage as he swept down Italy. Pompey, for his part, was not sorry to have a pretext for moving eastward toward the scene of his early triumphs, where his military prestige and his personal influence would cause all the client states to rally round him, and the sulky and suspicious nobles would find themselves overshadowed. So he crossed the Adriatic, leaving the large veteran army in Spain, which was under his orders, to take care of itself. Thither Caesar proceeded as soon as he had secured Italy, bent on making sure of the West before doing anything else. When the Spanish legions were beaten, he lost no time in following Pompey, who had found the respite all too short for drilling his large but raw force of Romans, and organizing the masses of Asiatics whom he had summoned to his standard. In the campaign that ensued, the conqueror of the East fully maintained his old military reputation; but at length, driven by the clamor of the nobles to risk a pitched battle, he suffered a crushing defeat on the field of Pharsalia (B.C. 48). Flying to Egypt, still an independent kingdom, he was assassinated by order of the government.