Marcellus is the first husband of Augustus’ daughter Julia. Marcellus is a favorite of Augustus and is his first named heir. Livia pretends to favor both Marcellus and Augustus’ best friend and army comrade Agrippa in order to promote jealousy between the two. Jellously and a fude developes between Agrippa and Marcellus. Agrippa withdraws himself some Rome so that he will not be in the middle of the conflict. Marcellus is elected to a city magistracy, and shortly afterwards dies, a victim of Livia's poison.
After Marcellus' death, Augustus begs Agrippa to return to Rome and offers to marry him and Julia. Julia is horrified to be married to a man who is 30 years older than she is. When Agrippa's services are no longer essential to Rome, Livia poisons him. Before his death he and Julia have three sons, Gaius, Lucius and Postumus.
Gaius and his brother Lucius are favored by Augustus as potential heirs. Shortly after Gaius becomes the governor of Asia Minor, Livia poisons him. Lucius is also seen as an obstacle to Tiberius' position as heir, Lucius is poisoned at Livia's orders during a voyage from Spain.
The youngest son of Julia and Agrippa; Augustus' grandson, Postumus is known for his physical strength and benevolent nature. When Augustus names him his heir, Livia plots to have him banished and sets up a fake rape situation with Livilla, Claudius' sister and Postumus' long-time love. Postumus is captured and imprisoned on an island but not before he has told Claudius that Livia is the cause of his banishment. Augustus eventually discovers that Postumus is innocent and removes him from the island. When Livia discovers that Augustus plans to position Postumus as his heir again, she poisons Augustus but is unable to find Postumus. Eventually Postumus comes out of hiding and attempts to rally support against Tiberius. He fails and is captured by Tiberius and beheaded.
It is also rumored and Livia never admitted to it, that she also poisoned her first husband in order to marry Augustus.
