Portrait of Tiberius. Circa 30 AD. Marble.
Tiberius would later marry Augustus' daughter (from his marriage to Scribonia), Julia the Elder, and even later be adopted by Augustus, by which act he officially became a Julian, bearing the name Tiberius Julius Caesar. The subsequent emperors after Tiberius would continue this blended dynasty of both families for the following thirty years; historians have named it the Julio-Claudian dynasty.
In relations to the other emperors of this dynasty, Tiberius was the stepson of Augustus, grand-uncle of Caligula, paternal uncle of Claudius, and great-grand uncle of Nero. His 22-and-a-half-year reign would be the longest after Augustus's until Antoninus Pius, who surpassed his reign by a few months in 161.
Tiberius was one of the greatest Roman generals; his conquest of Pannonia, Dalmatia, Raetia, and temporarily, parts of Germania, laid the foundations for the northern frontier. But he came to be remembered as a dark, reclusive, and sombre ruler who never really desired to be emperor; Pliny the Elder called him tristissimus hominum, "the gloomiest of men."
After the death of Tiberius’ son Drusus Julius Caesar in 23 AD, he became more reclusive and aloof. In 26 AD Tiberius removed himself from Rome and left administration largely in the hands of his unscrupulous Praetorian prefects Lucius Aelius Sejanus and Quintus Naevius Sutorius Macro.
Caligula, Tiberius' grand-nephew and adopted grandson, succeeded Tiberius upon his death.