was born at Tolosa in Gaul, and received in his boyhood the surname of Becco, which signified in the Gallic language a cock's beak. (Suet. Vitell. 18; Martial, 9.100,) He afterwards went to Rome, and rose to the dignity of a senator; but having been condemned of forgery (falsum) under the lex Cornelia in the reign of Nero, he was expelled from the senate, and banished from the city. (Tac. Ann. 14.40; D. C. 65.9). After the death of Nero (A. D. 68), he was restored to his former rank by Galba, and appointed to the command of the seventh legion, which was stationed in Pannonia. It was believed that he subsequently wrote to Otho, offering to take the command of his forces; but as Otho would not employ him, he gave him no support in his struggle with Vitellius. When the fortunes of the latter began to decline (A. D. 69), Antonius was one of the first generals in Europe who declared in favour of Vespasian; and he rendered him the most important services. He was well fitted to play a conspicuous part in a civil war, being bold in action, ready in speech, unscrupulous in the use of means, equally ready to plunder and to bribe, and possessing considerable military abilities. It was by his influence that the legions in Moesia, as well as those in Pannonia, espoused the side of Vespasian. When the other generals of Vespasian were of opinion that they should remain in Pannonia, and await the arrival of Mucianus, who was marching from the East at the head of a powerful body of Vespasian's troops, Antonius on the contrary urged an immediate invasion of Italy. His energy overruled all opposition. Without waiting till the army was ready, Antonius, with a small body of picked troops, and accompanied by Arrius Varus, who had gained great renown under Corbulo in the Armenian war, crossed the Alps and pushed forwards into Italy. Here he met with great success; he obtained possession of several towns in Transpadane Gaul, and at Patavium was joined by two legions which had followed him from the north. At Patavium he allowed his troops a short time for repose, and then marched upon Verona, which also fell into his power. Meantime Alienus Caecina, who had been sent by Vitellius at the head of a large army to oppose Antonius, adopted no active measures against him, though with his superior forces he might easily have driven him out of Italy. Shortly afterwards three more legions crossed the Alps and joined Antonius, who was now at the head of five legions. His authority however was shared by two generals of consular rank, T. Ampius Flavianus, the governor of Pannonia, and Aponius Saturninus, the governor of Moesia; but an insurrection of the soldiers delivered him from these rivals, and obliged them to flee from the camp. Antonius affected great indignation at these proceedings, but it was believed by many that the mutiny had been instigated by himself that he might obtain the sole command. The army of Caecina meanwhile had been thrown into great confusion by the treason of their general Caecina, who had endeavoured to persuade his troops to desert Vitellius and espouse the cause of Vespasian; but not succeeding in his attempt, he had been thrown into chains, and new generals elected by the soldiers in his stead. Antonius resolved to avail himself of these favourable circumstances for making an immediate attack upon the army of Vitellius. He accordingly broke up from his quarters at Verona, and advanced as far as Bedriacum, a small town at no great distance from Cremona. At Bedriacum the decisive battle was fought. The imprudence of Arrius Varus, who had charged the enemy too soon and was driven back with loss, threw the army of Antonius into confusion, and nearly caused the loss of the battle. Antonius only arrested the flight by killing one of his own standard-bearers who was in the act of flying, and by leading the men against the enemy with the standard in his hand. Victory at length declared for Antonius, and the enemy fled in confusion to Cremona, from which town they had marched to Bedriacum. In the night Antonius was attacked by another army of Vitellius, consisting of six legions, which had been stationed at Hostilia, thirty miles distant, and which had immediately set out against Antonius upon hearing of the defeat of their comrades. The skill and valour of Antonius again secured the victory for his troops after another hard-fought battle. In the morning he marched against Cremona, which was at length obliged to submit to him after a vigorous defence. The unhappy city was given up to plunder and flames; and at the end of four days of incessant pillage, during which the most horrible atrocities were perpetrated, the entire city was levelled to the ground.

Hitherto Antonius had acted with moderation and caution; but, as frequently happens, success revealed his cruel character, and brought forth to public view the avarice, pride, and other vices which were inherent in his nature. Henceforth he treated Italy like a conquered country; and in order to maintain his popularity with the soldiers. allowed them every kind of licence. Mucianus, who was jealous of his success, and who wished to reserve to himself the glory of putting an end to the war, wrote to Antonius, recommending caution and delay, though he worded his letters in such a manner that the responsibility of all movements was thrown upon Antonius. But to the officers of Antonius he expressed himself with more openness, and thus endeavoured to keep Antonius in the north of Italy. Antonius, however, was not of a temper to brook such interference, and he therefore wrote to Vespasian, extolling his own exploits, and covertly attacking Mucianus. Without troubling himself about the wishes of the latter, he crossed the Apennines in the middle of winter, and marched straight upon Rome. Upon reaching Ocriculum, however, he halted for some days. His soldiers, whose appetites had been whetted by the plunder of Cremona, and who were impatient to glut themselves with the spoils of Rome, were indignant at this delay, and accused their general of treachery. It is probable that Antonius, who saw that it would be difficult to restrain his soldiers, feared the general odium, as well as the displeasure of Vespasian, if his troops were to sack the imperial city. But whatever were his motives or intentions, circumstances occurred which put an end to his inactivity. News arrived that Flavius Sabinus had taken refuge in the Capitol, and that he was there besieged by the Vitellian troops. Thereupon Antonius immediately marched upon Rome, but before he could reach the city the Capitol was burnt, and Sabinus killed. Upon arriving at the suburbs, he endeavoured to prevent his troops from entering the city till the following day; but the soldiers, who saw the prey before their eyes, demanded to be led forthwith to the attack. Antonius was obliged to yield; he divided his army into three bodies, and gave orders for the assault. The troops of Vitellius fought with the courage of despair; driven out of the suburbs, they continued the combat in the streets of the city, and the struggle continued for many days. At length the work of butchery came to an end; the soldiers of Vitellius were everywhere destroyed, and the emperor himself put to death. Thereupon Domitian, who was in Rome, received the name of Caesar; Arrius Varus was entrusted with the command of the Praetorian troops; but the government and all real power was in the hands of Antonius. His rapacity knew no bounds, and he kept plundering the emperor's palace, as if he had been at the sack of Cremona. The subservient senate voted him the consular ornaments ; but his rule lasted only for a short time. Mucianus reached Rome soon after the death of Vitellius, and was immediately received by the senate and the whole city, as their master. But though Antonius was thus reduced to a subordinate position in the state, Mucianus was still jealous of him. He, therefore, would not allow him to accompany Domitian in his expedition into Germany; at which Antonius was so indignant that he repaired to Vespasian, who was at Alexandria. He was not received by Vespasian in the distinguished manner which he had expected, and to which he thought that he was entitled; for though the emperor treated him with kindness and consideration on account of the great services he had rendered him, he secretly regarded him with dislike and suspicion, in consequence of the accusations of Mucianus, and the haughty conduct of Antonius himself.