The situation of Julian required a vigorous and immediate resolution. He had discovered, from intercepted letters, that his adversary, sacrificing the interest of the state to that of the monarch, had again excited the Barbarians to invade the provinces of the West. The position of two magazines, one of them collected on the banks of the Lake of Constance, the other formed at the foot of the Cottian Alps, seemed to indicate the march of two armies; and the size of those magazines, each of which consisted of six hundred thousand quarters of wheat, or rather flour, was a threatening evidence of the strength and numbers of the enemy who prepared to surround him. But the Imperial legions were still in their distant quarters of Asia; the Danube was feebly guarded; and if Julian could occupy, by a sudden incursion, the important provinces of Illyricum, he might expect that a people of soldiers would resort to his standard, and that the rich mines of gold and silver would contribute to the expenses of the civil war. He proposed this bold enterprise to the assembly of the soldiers; inspired them with a just confidence in their general, and in themselves; and exhorted them to maintain their reputation of being terrible to the enemy, moderate to their fellow-citizens, and obedient to their officers. His spirited discourse was received with the loudest acclamations, and the same troops which had taken up arms against Constantius, when he summoned them to leave Gaul, now declared with alacrity, that they would follow Julian to the farthest extremities of Europe or Asia. The oath of fidelity was administered; and the soldiers, clashing their shields, and pointing their drawn swords to their throats, devoted themselves, with horrid imprecations, to the service of a leader whom they celebrated as the deliverer of Gaul and the conqueror of the Germans. This solemn engagement, which seemed to be dictated by affection rather than by duty, was singly opposed by Nebridius, who had been admitted to the office of Prætorian præfect. That faithful minister, alone and unassisted, asserted the rights of Constantius, in the midst of an armed and angry multitude, to whose fury he had almost fallen an honorable, but useless sacrifice. After losing one of his hands by the stroke of a sword, he embraced the knees of the prince whom he had offended. Julian covered the præfect with his Imperial mantle, and, protecting him from the zeal of his followers, dismissed him to his own house, with less respect than was perhaps due to the virtue of an enemy. The high office of Nebridius was bestowed on Sallust; and the provinces of Gaul, which were now delivered from the intolerable oppression of taxes, enjoyed the mild and equitable administration of the friend of Julian, who was permitted to practise those virtues which he had instilled into the mind of his pupil.

The hopes of Julian depended much less on the number of his troops, than on the celerity of his motions. In the execution of a daring enterprise, he availed himself of every precaution, as far as prudence could suggest; and where prudence could no longer accompany his steps, he trusted the event to valor and to fortune. In the neighborhood of Basil he assembled and divided his army. One body, which consisted of ten thousand men, was directed under the command of Nevitta, general of the cavalry, to advance through the midland parts of Rhætia and Noricum. A similar division of troops, under the orders of Jovius and Jovinus, prepared to follow the oblique course of the highways, through the Alps, and the northern confines of Italy. The instructions to the generals were conceived with energy and precision: to hasten their march in close and compact columns, which, according to the disposition of the ground, might readily be changed into any order of battle; to secure themselves against the surprises of the night by strong posts and vigilant guards; to prevent resistance by their unexpected arrival; to elude examination by their sudden departure; to spread the opinion of their strength, and the terror of his name; and to join their sovereign under the walls of Sirmium. For himself Julian had reserved a more difficult and extraordinary part. He selected three thousand brave and active volunteers, resolved, like their leader, to cast behind them every hope of a retreat; at the head of this faithful band, he fearlessly plunged into the recesses of the Marcian, or Black Forest, which conceals the sources of the Danube; and, for many days, the fate of Julian was unknown to the world. The secrecy of his march, his diligence, and vigor, surmounted every obstacle; he forced his way over mountains and morasses, occupied the bridges or swam the rivers, pursued his direct course, without reflecting whether he traversed the territory of the Romans or of the Barbarians, and at length emerged, between Ratisbon and Vienna, at the place where he designed to embark his troops on the Danube. By a well-concerted stratagem, he seized a fleet of light brigantines, as it lay at anchor; secured a apply of coarse provisions sufficient to satisfy the indelicate, and voracious, appetite of a Gallic army; and boldly committed himself to the stream of the Danube. The labors of the mariners, who plied their oars with incessant diligence, and the steady continuance of a favorable wind,