Tiberius was born in 42 BC, the son of the aristocratic Tiberius Claudius Nero and Livia Drusilla.
When Tiberius was two, his father had to flee Rome from the second triumvirate (Octavian, Lepidus, Mark Antony) because of his republican beliefs (he had fought against Octavian in the civil wars).
Though Tiberius, a large, strong man, had been groomed by Augustus as his successor, he was actually the fourth choice after Agrippa, husband of Augustus' only daughter Julia, and their sons, Gaius and Lucius, all three of whom died in the lifetime of Augustus.
He enjoyed good health, though his skin sometimes suffered from 'skin eruptions' - most likely rashes of some sort. Also he had a great fear of thunder. He profoundly disliked gladiatorial games and made no attempt in pretending to do so, in order to win popularity with the ordinary people of Rome.
In 25 BC he already held his first post as an officer in Cantabria. By 20 BC he accompanied Augustus to the east to reclaim the standards lost to the Parthians by Crassus thirty-three years earlier.
Then, after the death of Agrippa in 12 BC, Augustus forced a reluctant Tiberius to divorce his wife Vipsania, in order to marry, Julia, Augustus' own daughter and widow of Agrippa.
Then, with the death of the two apparent heirs Gaius and Lucius, Augustus called Tiberius out of retirement, reluctantly recognizing him as his successor. In AD 4 Augustus adopted him, adding the words 'This I do for reasons of state.' If these words proved anything, then it was, that Augustus was as reluctant to make Tiberius his successor as Tiberius appeared to be reluctant to become it.
In any case, Tiberius was granted tribunician powers for ten years and was handed command of the Rhine frontier.
So, from AD 4 to 6 Tiberius again campaigned in Germany. The follwing three years he spent putting down rebellions in Pannonia and Illyricum. After this he restored the Rhine frontier after Rome's defeat at the Varian disaster.
In AD 13 Tiberius' constitutional powers were renewed on equal terms with those of Augustus, making his succession inevitable, as the elderly Augustus died in AD 14.
Tiberius was summoned back not by the senate but by his elderly mother, Livia, widow of Augustus.
At the very beginning of his reign, the powerful Danube and Rhine legions mutinied, because some of Augustus promises regarding their terms of service and benefits were not met. Also they had sworn allegiance neither to the state, nor to Tiberius, but to Augustus. Though, after initial difficulties, these disturbances were eventually quelled.
What followed were several years of intrigue at court, as candidates to succeed Tiberius (and their wives, daughters, friends, etc) manoeuvered for position. Tiberius had probably no part in any of this. But sensing it happening around him unsettled him and only further contributed to his indecision in matters of government.
Germanicus then tried to bring back the German territories lost with the Varian disaster with three successive military campaigns, but failed in achieving this. In AD 19 Germanicus died in Antioch, where he by then held a high command in the east. Some rumours state that Gnaeus Calpurnius Piso, governor of Syria and confidant of Tiberius, had poisoned him. Piso was tried for murder and ordered to commit suicide, but the suspicion remained that he had been acting for the emperor.
Finally in AD 26 Tiberius had had enough. Because he had probably always been happiest when away from the capital and its evelasting intrigue, Rome's emperor simply departed to his holiday mansion on the isle of Capreae (Capri), never to return to the city.
He left the government in the hands of Lucius Aelius Sejanus, the praetorian prefect. Sejanus believed himself a potential successor of the emperor, and was conspiring against Tiberius whilst removing any other possible candidates to the throne.
Enjoying near unlimited power in Rome, Sejanus was free to act and moved the two immediate heirs to the throne, Nero Caesar and Drusus Caesar, aside on what were most likely ficticious charges of treason. Nero Caesar was banished to an island, Drusus was imprisoned in the cellar of the imperial palace. It was long and both were dead. Nero Caesar was ordered to commit suicide, Drusus Caesar was starved to death.
This left only one more surviving son of Germanicus as heir to the throne, the young Gaius (Caligula).
Sejanus' power reached its high-point when he held consular office in the same year as Tiberius (AD 31). But then he brought about his own downfall by plotting the elimination of nineteen year-old Gaius.
Tiberius might have retired to his island for his dislike of politics and intrigues. But when he saw teh necessity he could still ruthlessly exercise power. Command of the pratorian guard was secretely transferred to one of Tiberius' friends, Naevius Cordus Sertorius Macro, who on 18 October AD 31 had Sejanus arrested during a meeting of the senate. A letter by the emperor to the senate was then read out expressing Tiberius' suspicions. Sejanus was duly executed, his corpse dragged through the streets and thrown into the Tiber. His family and many of his supporters suffered similar fates.
Tiberius then drew up his will, indecisive to the very end, he left Gaius and Gemellus (Tiberius' own grandson) as joint heirs, but is was obvious that it would be by now twenty-four year-old Gaius who would truly succeed him. For one Gemellus was still an infant. But also because Tiberius appeared to suspect that Gemellus was in fact an adulterous child of Sejanus.
There were many rumours suggesting that Tiberius' retirement home on Capri was a palace of never ending sexual excesses, however, other reports state that Tiberius had moved there 'with only a few companions', who consisted mainly of Greek intellectuals whose conversation Tiberius enjoyed.
Tiberius last years were still fraught with morbid mistrust, and an increase of treason trials gave this time a air of terror.
It was in early AD 37 that Tiberius fell ill while travelling in Campania. He was taken to his villa in Misenum in order to recover, but died there on 16 March AD 37.