They came in 649 under their king Boiorix, on this occasion seriously meditating an inroad into Italy. They were opposed on the right bank of the Rhone by the proconsul Caepio, on the left by the consul Gnaeus Mallius Maximus and by his legate, the consular Marcus Aurelius Scaurus, under him at the head of a detached corps. The first onset fell on the latter; he was totally defeated and brought in person as a prisoner to the enemy's head-quarters, where the Cimbrian king, indignant at the proud warning given to him by the captive Roman not to venture with his army into Italy, put him to death. Maximus thereupon ordered his colleague to bring his army over the Rhone: the latter complying with reluctance at length appeared at Arausio (Orange) on the left bank of the river, where the whole Roman force now stood confronting the Cimbrian army, and is alleged to have made such an impression by its considerable numbers that the Cimbri began to negotiate. But the two leaders lived in the most vehement discord.

Maximus, an insignificant and incapable man, was as consul the legal superior of his prouder and better born, but not better qualified, proconsular colleague Caepio; but the latter refused to occupy a common camp and to devise operations in concert with him, and still, as formerly, maintained his independent command. In vain deputies from the Roman senate endeavoured to effect a reconciliation; a personal conference between the generals, on which the officers insisted, only widened the breach. When Caepio saw Maximus negotiating with the envoys of the Cimbri, he fancied that the latter wished to gain the sole credit of their subjugation, and threw himself with his portion of the army alone in all haste on the enemy. He was utterly annihilated, so that even his camp fell into the hands of the enemy (6 Oct. 649); and his destruction was followed by the no less complete defeat of the second Roman army. It is asserted that 80,000 Roman soldiers and half as many of the immense and helpless body of camp-followers perished, and that only ten men escaped: this much is certain, that only a few out of the two armies succeeded in escaping, for the Romans had fought with the river in their rear. It was a calamity which materially and morally far surpassed the day of Cannae. The defeats of Carbo, of Silanus, and of Longinus had passed without producing any permanent impression on the Italians. They were accustomed to open every war with disasters; the invincibleness of the Roman arms was so firmly established, that it seemed superfluous to attend to the pretty numerous exceptions. But the battle of Arausio, the alarming proximity of the victorious Cimbrian army to the undefended passes of the Alps, the insurrections breaking out afresh and with increased force both in the Roman territory beyond the Alps and among the Lusitanians, the defenceless condition of Italy, produced a sudden and fearful awakening from these dreams. Men recalled the never wholly forgotten Celtic inroads of the fourth century, the day on the Allia and the burning of Rome: with the double force at once of the oldest remembrance and of the freshest alarm the terror of the Gauls came upon Italy; through all the west people seemed to be aware that the Roman empire was beginning to totter. As after the battle of Cannae, the period of mourning was shortened by decree of the senate[21]. The new enlistments brought out the most painful scarcity of men. All Italians capable of bearing arms had to swear that they would not leave Italy; the captains of the vessels lying in the Italian ports were instructed not to take on board any man fit for service. It is impossible to tell what might have happened, had the Cimbri immediately after their double victory advanced through the gates of the Alps into Italy. But they first overran the territory of the Arverni, who with difficulty defended themselves in their fortresses against the enemy; and soon, weary of sieges, set out from thence, not to Italy, but westward to the Pyrenees.

If the torpid organism of the Roman polity could still of itself reach a crisis of wholesome reaction, that reaction could not but set in now, when, by one of the marvellous pieces of good fortune, in which the history of Rome is so rich, the danger was sufficiently imminent to rouse all the energy and all the patriotism of the burgesses, and yet did not burst upon them so suddenly as to leave no space for the development of their resources. But the very same phenomena, which had occurred four years previously after the African defeats, presented themselves afresh. In fact the African and Gallic disasters were essentially of the same kind. It may be that primarily the blame of the former fell more on the oligarchy as a whole, that of the latter more on individual magistrates; but public opinion justly recognized in both, above all things, the bankruptcy of the government, which in its progressive development imperilled first the honour and now the very existence of the state. People just as little deceived themselves then as now regarding the true seat of the evil, but as little now as then did they make even an attempt to apply the remedy at the proper point. They saw well that the system was to blame; but on this occasion also they adhered to the method of calling individuals to account - only no doubt this second storm discharged itself on the heads of the oligarchy so much the more heavily, as the calamity of 649 exceeded in extent and peril that of 645. The sure instinctive feeling of the public, that there was no resource against the oligarchy except the tyrannis, was once more apparent in their readily entering into every attempt by officers of note to force the hand of the government and, under one form or another, to overturn the oligarchic rule by a dictatorship.

It was against Quintus Caepio that their attacks were first directed; and justly, in so far as he had primarily occasioned the defeat of Arausio by his insubordination, even apart from the probably well-founded but not proved charge of embezzling the Tolosan booty; but the fury which the opposition displayed against him was essentially augmented by the fact, that he had as consul ventured on an attempt to wrest the posts of jurymen from the capitalists[22]. On his account the old venerable principle, that the sacredness of the magistracy should be respected even in the person of its worst occupant, was violated; and, while the censure due to the author of the calamitous day of Cannae had been silently repressed within the breast, the author of the defeat of Arausio was by decree of the people unconstitutionally deprived of his proconsulship, and - what had not occurred since the crisis in which the monarchy had perished - his property was confiscated to the state-chest (649?). Not long afterwards he was by a second decree of the burgesses expelled from the senate (650).

But this was not enough; more victims were desired, and above all Caepio's blood. A number of tribunes of the people favourable to the opposition, with Lucius Appuleius Saturninus and Gaius Norbanus at their head, proposed in 651 to appoint an extraordinary judicial commission in reference to the embezzlement and treason perpetrated in Gaul; in spite of the de facto abolition of arrest during investigation and of the punishment of death for political offences, Caepio was arrested and the intention of pronouncing and executing in his case sentence of death was openly expressed. The government party attempted to get rid of the proposal by tribunician intervention; but the interceding tribunes were violently driven from the assembly, and in the furious tumult the first men of the senate were assailed with stones. The investigation could not be prevented, and the warfare of prosecutions pursued its course in 651 as it had done six years before; Caepio himself, his colleague in the supreme command Gnaeus Mallius Maximus, and numerous other men of note were condemned: a tribune of the people, who was a friend of Caepio, with difficulty succeeded by the sacrifice of his own civic existence in saving at least the life of the chief persons accused[23].