He made his first campaign, as a military tribune, in the Cantabrian war.A. U. C. 728. Afterwards he led an army into the East,A.U.C. 734 where he restored the kingdom of Armenia to Tigranes; and seated on a tribunal, put a crown upon his head. He likewise recovered from the Parthians the standards which they had taken from Crassus. He next governed, for nearly a year, the province of Gallia Comata, which was then in great disorder, on account of the incursions of the barbarians, and the feuds of the chiefs. He afterwards commanded in the several wars against the Rhaetians, Vindelicians, Pannonians, and Germans. In the Rhaetian and Vindelician wars, he subdued the nations in the Alps; and in the Pannonian wars the Bruci, and the Dalmatians. In the German war, he transplanted into Gaul forty thousand of the enemy who had submitted, and assigned them lands near the banks of the Rhine. For these actions, he entered the city with an ovation, but riding in a chariot, and is said by some to have been the first that ever was honoured with this distinction. He filled early the principal offices of state; and passed through the quaestorship,A.U.C. 737 praetorship,A.U.C. 741 and consulatesA.U.C. 747 almost successively. After some interval, he was chosen consul a second time, and held the tribunitian authority during five years.

Surrounded by all this prosperity, in the prime of life and in excellent health, he suddenly formed the resolution of withdrawing to a greater distance from Rome.A.U.C. 748 It is uncertain whether this was the result of disgust for his wife, whom he neither durst accuse nor divorce, and the connection with whom became every day more intolerable; or to prevent that indifference towards him, which his constant residence in the city might produce; or in the hope of supporting and improving by absence his authority in the state, if the public should have occasion for his service. Some are of opinion, that as Augustus's sons were now grown up to years of maturity, he voluntarily relinquished the possession he had long enjoyed of the second place in the government, as Agrippa had done before him; who, when M. Marcellus was advanced to public offices, retired to Mitylene, that he might not seem to stand in the way of his promotion, or in any respect lessen him by his presence. The same reason likewise Tiberius gave afterwards for his retirement; but his pretext at this time was, that he was satiated with honours, and desirous of being relieved from the fatigue of business; requesting therefore that he might have leave to withdraw. And neither the earnest entreaties of his mother, nor the complaint of his father-in-law made even in the senate, that he was deserted by him, could prevail upon him to alter his resolution. Upon their persisting in the design of detaining him, he refused to take any sustenance for four days together. At last, having obtained permission, leaving his wife and son at Rome, he proceeded to Ostia,Ostia, at the mouth of the Tiber, about thirteen miles from the city, was founded by Ancus Martins. Being the port of a city like Rome, it could not fail to become opulent; and it was a place of much resort, ornamented with fine edifices, and the environs " never failing of pasture in the summer time, and in the winter covered with roses and other flowers." The port having been filled up with the depositions of the Tiber, it became deserted, and is now abandoned to misery and malaria. The bishopric of Ostia being the oldest in the Roman church, its bishop has always retained some peculiar privileges. without exchanging a word with those who attended him, and having enbraced but very few persons at parting.