Short answers, pulled from the story.
Tiberius became emperor on the 19th of August AD 14, following the death of Augustus, and reigned until his own death on the 16th of March AD 37 - a total of more than twenty-two years. He was 55 years old when he took power and died months before his 78th birthday.
Tiberius withdrew to Rhodes in 6 BC, likely driven by his forced marriage to Julia the Elder and his forbidden longing for his first wife Vipsania. Tacitus understood this as the true reason. He moved permanently to the island of Capri in AD 26, and his retreat there has been linked by Tacitus to embarrassment over his baldness and a disfiguring facial ailment.
Lucius Aelius Sejanus was Praetorian Prefect from AD 15 and had served the imperial family for almost twenty years before Tiberius withdrew to Capri. He was left in control of the entire state mechanism and command of the Praetorian Guard, which had been consolidated into Rome itself with between 6,000 and 9,000 troops. In AD 31 Tiberius had him condemned and executed within the week for plotting to seize the Principate.
Tiberius died at Misenum on the 16th of March AD 37. Tacitus and Cassius Dio describe him being smothered with his own bedclothes by Macro after appearing to revive when Caligula had already been acknowledged as his successor. Suetonius says he simply fell dead after trying to rise from his couch. Seneca the Elder, Josephus, Pliny, and Philo describe a natural death without dramatic detail.
Tiberius left the imperial treasury with nearly 3 billion sesterces at his death. He achieved this through fiscal restraint, choosing consolidation over costly military campaigns, using diplomacy alongside military threats, and avoiding minor conflicts at the frontiers.
According to the Gospels, Jesus of Nazareth preached and was executed during the reign of Tiberius, by the authority of Pontius Pilate, the Roman governor of Judaea. Luke 3:1 places the beginning of John the Baptist's ministry in the fifteenth year of Tiberius's reign. The Christian History Institute does not list Tiberius as an emperor who persecuted Christians.