Tiberius Julius Caesar Augustus ( ty-BEER-ee-əs; 16 November 42 BC – 16 March AD 37) was Roman emperor from AD 14 until 37. He succeeded his stepfather Augustus, the first Roman emperor. Tiberius was born in Rome in 42 BC to politician Tiberius Claudius Nero and his wife, Livia Drusilla. In 38 BC, Tiberius's mother divorced his father and married Augustus. Following the untimely deaths of Augustus's two grandsons and adopted heirs, Gaius and Lucius Caesar, Tiberius was designated Augustus's successor. 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. They had a son, Drusus Julius Caesar. After Agrippa died, Augustus insisted that Tiberius divorce Vipsania and marry Agrippa's widow, Augustus' own daughter (Tiberius's step-sister) Julia; Tiberius relented.