It was in that period of civic strife, when factions and parties struggled for ascendency--when the Gracchi were both reformers and demagogues, patriots and disorganizes, heroes and martyrs--when fortunate generals aimed at supreme power, and sought to overturn the liberties of their country, that Rome was seriously threatened by the barbarians. Both Celts and Teutones, from Gaul and Germany, formed a general union for the invasion of Italy. They had successively defeated five consular armies, in which one hundred and twenty thousand men were slain. They rolled on like a devastating storm--some three hundred thousand warriors from unconquered countries beyond the Alps. They were met by Marius the hero of the African war, who had added Numidia, to the empire--now old, fierce, and cruel, a plebeian who had arisen by force of military genius--and the Gaulish hordes were annihilated on the Rhone and the Po. The Romans at first viewed those half-naked warriors--so full of strength and courage, so confident of victory, so reckless of life, so impetuous and savage--with terror and awe. But their time had not yet come. Numbers were of no avail against science, when science was itself directed by genius and sustained by enthusiasm. The result of the decisive battles of Aquae Sextiae and Vercellae was to roll back the tide of northern immigration for three hundred years, and to prepare the way for the conquests of Caesar in Gaul. [Sidenote: The Social War.] [Sidenote: Rise of Sulla.] Then followed that great insurrection of the old states of Italy against their imperious mistress--their last struggle for independence, called the Social War, in which three hundred thousand of the young men of Italy fell, and in which Sulla so much distinguished himself as to be regarded as the rival of Marius, who had ruled Rome since the slaughter of the Cimbrians and Teutones. Sulla, who had served under Marius in Africa, dissolute like Antony, but cultivated like Caesar--a man full of ambition and genius, and belonging to one of the oldest and proudest patrician families, the Cornelian gens--was no mean rival of the old tyrant and demagogue, and he was sent against Mithridates, the most powerful of all the Oriental kings. This Asiatic potentate had encouraged the insurgents in Italy, and was also at war with the Romans. Marius viewed with envy and hatred the preference shown to Sulla in the conduct of the Mithridatic War, and succeeded, by his intrigues and influence with the people, in causing Sulla to be superseded, and himself to be appointed in his place. [Sidenote: Civil wars between Marius and Sulla.]