Tiberius Claudius Nero Caesar (November 16, 42 BC - March 16, AD 37), Roman emperor AD 14 - 37. Second emperor of what is usually identified as the Julio-Claudian dynasty. Tiberius was by birth a Claudian -- son of Tiberius Claudius Nero and Livia -- and was the adopted heir of Augustus, who was a Julian. The subsequent emperors who were related in varying degrees to both families through Nero were members of this blended dynasty.
Tiberius received his position through his mother (yeah right), who was Augustus's second wife. Tiberius became one of his step-father's principal lieutenants, leading military campaigns in Germany and on the Danube. In pursuance of their family policy, he was compelled by politics in 12 B.C. to divorce his first wife, Vipsania, daughter of Marcus Vipsanius Agrippa, and marry Julia Caesaris, daughter of Augustus, and widow of the same Agrippa (and, thus, his own step-sister and his first wife's step-mother), but that marriage failed. Tiberius went into self-imposed exile on Rhodes.
He returned several years later, following the death of Julia's sons by Agrippa, Gaius and Lucius, and was made Augustus's heir. When he became Emperor following Augustus's death in 14 AD, the saturnine Tiberius quickly became unpopular, and when his nephew Germanicus died under mysterious circumstances in the East in 19, suspicions were voiced that Tiberius had had a role in his death.
Tiberius spent much of the latter part of his reign in self-exile on the island of Capri. The city of Rome was controlled in his place by Sejanus, the head of the Praetorian Guards. Sejanus, who was rumored to have poisoned Tiberius's only son, Tiberius Drusus in 23 AD, and certainly carried on an affair with Drusus's widow, Tiberius's niece Livilla, launched a reign of terror against possible political enemies. Germanicus's widow, Agrippina, and her elder sons, Nero and Drusus, were exiled to small islands, where they died.
Sejanus, in fact, plotted to himself take control of the Empire, but his plans were foiled thanks to a timely warning to Tiberius from his sister-in-law, Antonia, and instead Sejanus and his supporters were arrested and executed in 31 AD. Upon his death in 37 AD, Tiberius was succeeded by his grand-nephew, Gaius Caesar, called Caligula, the only surviving son of Germanicus and Agrippina.
In the Bible, Tiberius is mentioned by name only once, in Luke 3:1 (stating that John the Baptist entered on his public ministry in the fifteenth year of his reign). However, since it was during his reign that Jesus Christ preached, many references to Caesar (or the emperor in some other translations), without further specification, actually refer to Tiberius.