Nero Julius Caesar (c. AD 6–31) was the adopted grandson and heir of the Roman Emperor Tiberius, alongside his brother Drusus. Born into the prominent Julio-Claudian dynasty, Nero was the son of Tiberius' general and heir, Germanicus. After the deaths of his father and of Tiberius' son, Drusus the Younger, Nero and his brother Drusus were adopted together by Tiberius in September AD 23. As a result of being heirs of the emperor, he and his brother enjoyed accelerated political careers. Sejanus, prefect of the Praetorian Guard, had become powerful in Rome and is believed by ancient writers such as Suetonius and Tacitus to have been responsible for the downfall of Drusus the Younger. As the power of Sejanus grew, other members of the imperial family began to fall as well. In AD 29, Tiberius wrote a letter to the Senate attacking Nero and his mother, and the Senate had them both exiled. Two years later, he died in exile on the island of Ponza. His brother Drusus also died in exile in AD 33. Their deaths allowed for the adoption and ascension of their younger brother, Caligula, following the death of Tiberius in AD 37. Background and family Nero was born around AD 6 to Germanicus and Agrippina the Elder. Nero's paternal grandparents were Nero Claudius Drusus (Drusus the Elder) and Antonia Minor, daughter of Mark Antony and Octavia Minor. His maternal grandparents were Marcus Vipsanius Agrippa, a close friend of Augustus, and Augustus' daughter Julia the Elder. Nero had eight siblings: four brothers (Tiberius and Gaius Julius, who died young; Drusus Caesar; and Gaius, nicknamed "Caligula") , three sisters (Agrippina the Younger, Julia Drusilla, and Julia Livilla) and a brother or sister of unknown name (normally referenced as Ignotus). As a member of the Julio-Claudian dynasty, he was a close relative of all five Julio-Claudian emperors: his great-grandfather Augustus was the first emperor of the dynasty, his great-uncle Tiberius was the second emperor, his brother Gaius (Caligula) was the third emperor, his uncle Claudius was the fourth emperor, and his nephew Lucius Domitius (Nero) was the fifth and final emperor of the dynasty. Nero's father was the adopted son of Tiberius, who was himself the adoptive son of Augustus, whose adoptions were the result of the death of Gaius Caesar in February AD 4. Gaius, who was the heir of Augustus, had died of illness in Syria. Germanicus