Claudius:  Grandmother ... who killed Marcellus ?
Livia: I
Livia: did . The empire needed Agrippa more then it needed Marcellus . And then I poisoned Agrippa later because I knew that his wife was in love with Tiberius , but if Tiberius married her Augustus would make him emperor . My son botched that up of course ...
Claudius: And Julia 's sons by Agrippa , how did they die ?
Livia: Gaius I had poisoned while he was in Syria .
Claudius: You have a long reach .
Livia: The empire is very large , I need _ one _ . Lucius was drowned in a boating accident arranged by his friend Platius .
Claudius: And ... Postumus ?
Livia: You
Livia: were really fond of him were n't you ?
Claudius: Yes , grandmother .
Livia: He was useless . I had to get rid of Postumus ; he was a threat to Tiberius . Besides , he knew I had his mother banished .