Prior to this, Tiberius had proved himself an able diplomat and one of the most successful Roman generals: his conquests of Pannonia, Dalmatia, Raetia, and (temporarily) parts of Germania laid the foundations for the empire's northern frontier.

Early in his career, Tiberius was happily married to Vipsania, daughter of Augustus's friend, distinguished general and intended heir, Marcus Vipsanius Agrippa.

Tiberius allowed the worship of his divine Genius in only one temple, in Rome's eastern provinces, and promoted restraint in the empire-wide cult to the deceased Augustus.

While Drusus focused his forces in Gallia Narbonensis and along the German frontier, Tiberius combated the tribes in the Alps and within Transalpine Gaul, conquering Raetia.

Meanwhile, general Gaius Sentius Saturninus would depart east from Moguntiacum on the Rhine with two or three legions, pass through newly annexed Hermunduri territory, and attack the Marcomanni from the west.

In 6 BC, while on the verge of accepting command in the East and becoming the second-most powerful man in Rome, Tiberius announced his withdrawal from politics and retired to Rhodes.

[24] Some historians have speculated that Tiberius and Drusus were only ever intended as caretakers, and would have been swept aside once Julia's two sons by Agrippa, Gaius and Lucius, were adopted as Augustus's heirs and came of age.

[37][38] In AD 7, Agrippa Postumus, a younger brother of Gaius and Lucius, was disowned by Augustus and banished to the island of Pianosa, to live in solitary confinement.

However, according to Suetonius, after a two-year stint in Germania, which lasted from AD 10–12,[41]"Tiberius returned and celebrated the triumph which he had postponed, accompanied also by his generals, for whom he had obtained the triumphal regalia.

"[42] "Since the consuls caused a law to be passed soon after this that he should govern the provinces jointly with Augustus and hold the census with him, he set out for Illyricum on the conclusion of the lustral ceremonies.

[48][49][50] Tiberius already had the administrative and political powers of the Princeps, but he lacked the titles of Augustus and Pater Patriae ("Father of the country"), and refused the Civic Crown.

[56] The Roman legions in Pannonia and Germania had not been paid the bonuses promised to them by Augustus, and showed early signs of mutiny when it was clear that a response from Tiberius was not forthcoming.

[57] Germanicus and Tiberius's son, Drusus Julius Caesar, were dispatched with a small force to quell the uprising and bring the legions back in line.

They took control of the Teutoburg forest, where three Roman legions and their auxiliary cohorts, led by Publius Quinctilius Varus, had been annihilated by Germanic tribes several years before.

[78] Sejanus began a series of purge trials of Senators and wealthy equestrians (such as Curtius Atticus) in the city of Rome, removing those capable of opposing his power as well as extending the imperial (and his own) treasury.

Spies were set round them, who noted the sorrow of each mourner and followed the rotting corpses, till they were dragged to the Tiber, where, floating or driven on the bank, no one dared to burn or to touch them.

After Sejanus's fall, Tiberius's withdrawal from Rome was complete; the empire continued to run under the inertia of the bureaucracy established by Augustus, rather than through the leadership of the Princeps.

[90] However, Tiberius only made a half-hearted attempt at the end of his life to make Caligula a quaestor, and thus give him some credibility as a possible successor, while Gemellus himself was still only a teenager and thus completely unsuitable for some years to come.

He goes on to report that those who had moments before recognized Caligula as Augustus fled in fear of the emperor's wrath, while Macro took advantage of the chaos to have Tiberius smothered with his own bedclothes.

He wore his hair cut short at the front and sides but long in the back so it covered the nape of his neck in a style similar to the mullet, which Suetonius claims was a family tradition of the Claudian gens.

He also contracted a disfiguring facial ailment which may have been a severe case of herpes, an outbreak of which affected the Empire during his reign; Tiberius banned kissing at public functions in an effort to curtail its spread.

[109][110][111][112] Tacitus believed that embarrassment over his baldness and the disfigurement of his face may have been contributing factors to his retreat to Capri, and noted that he regularly attempted to cover his sores with plaster.

[114] Shortly before his death, he suffered an injury to his back while killing a boar with a javelin to open soldiers' games, which severely limited his mobility in his final days.

[115] As the Julio-Claudian Emperor who saw the most frontlines combat, and the one who actually led troops into battle, modern writers have concluded Tiberus' erratic and paranoid behavior later in life, as well as his alcohol intake, may have been the result of post-traumatic stress disorder.

[102][119] Rather than embark on costly campaigns of conquest, he chose to strengthen the existing empire by building additional bases, using diplomacy as well as military threats, and generally refraining from getting drawn into petty squabbles between competing frontier tyrants.

His characterisation of Tiberius throughout the first six books is mostly negative, and gradually worsens as his rule declines, identifying a clear breaking point with the death of his son Drusus in AD 23.

[134][135][136] During Tiberius's reign, Jews had become more prominent in Rome and Jewish and Gentile followers of Jesus began proselytising Roman citizens, increasing long-simmering resentments.

Josephus credits the banishment to a quartet of Jewish con artists – one of whom had fled prosecution in Judea for financial crimes – who successfully conspired to scam a Roman Matron out of a large quantity of money, silk, and gold, ostensibly to be sent for dedication in the Second Temple in Jerusalem.

The 2nd-3rd Century Christian apologist Tertullian said Tiberius approached the Senate with a request to acknowledge Christ as a deity, citing evidence of his miracles, and his resurrection following his crucifixion.

[144] In an otherwise Late Republican-era building, identifiable as such by its brickwork and flooring, the Dionysian-themed landscape and nature frescoes lining the walls are reminiscent of the illusionistic early Imperial paintings in his mother's own subterranean dining room.