Julio-Claudian dynasty reign as being strongly influenced by his mother Agrippina, his tutor Seneca, and the Praetorian Prefect Burrus, especially in the first year. He was made Emperor over his step-brother, Claudius' son Britannicus, who he had killed. Agrippina was believed to have poisoned Claudius, having allegedly poisoned her second husband Gaius Sallustius Crispus Passienus. She had also arranged the deaths of Caligula's third wife, Lollia Paulina and Messalina's mother Domitia Lepida the Younger. She saw that the dynasty's numbers dwindle with the execution of Marcus Junius Silanus Torquatus, a grandson of Julia the Younger, to strengthen Nero's claim, having previously arranged
Agrippina the Elder ties to the emperor. Historian Richard Alston says it is likely that either Tiberius or Livia were behind the exile of Agrippina's half-sister and the death of Postumus. He notes the death of Agrippina's mother, who starved herself to death amidst her exile in AD 14, linking her death to Tiberius' disdain for her. Agrippina was vocal about her feelings claiming that Germanicus was murdered to promote Drusus the Younger as Tiberius' heir, and worried that the birth of the Younger Drusus' twin sons would displace her own sons in the line of succession. Her fears proved to be unfounded,