Tiberius’ most serious dynastic rival was the surviving son of Agrippa and Julia, Agrippa Postumus. Tacitus (Annales 1.5) relates rumours that Augustus had visited Postumus in his island exile on Planasia, raising the possibility that Postumus would be summoned back to Rome. Fear of Agrippa Postumus’ political resurrection allegedly led to Livia hastening Augustus’ final illness. The story of an aged and infirm emperor making a secret journey to see his grandson seems far-fetched.

• Why would Augustus have secretly visited Postumus?
• How could such a visit have been kept secret? How might it have reached our historical sources?
• Who benefits from the story being circulated that the visit happened?

In any event, action was taken to remove the potential threat to Tiberius’ position. Agrippa Postumus was murdered.

The story is laid out in Tacitus, Annales 1.6, and is worth reading in full.

The opening crime of the new principate was the murder of Agrippa Postumus; who, though off his guard and without weapons, was with difficulty dispatched by a resolute centurion. In the senate Tiberius made no reference to the subject: his pretence was an order from his father, instructing the tribune in charge to lose no time in making away with his prisoner, once he himself should have looked his last on the world. It was beyond question that by his frequent and bitter strictures on the youth’s character Augustus had procured the senatorial decree for his exile: on the other hand, at no time did he harden his heart to the killing of a relative, and it remained incredible that he should have sacrificed the life of a grandchild in order to diminish the anxieties of a stepson. More probably, Tiberius and Livia, actuated in the one case by fear, and in the other by stepmotherly dislike, hurriedly procured the murder of a youth whom they suspected and detested. To the centurion who brought the usual military report, the emperor rejoined that he had given no instructions and the deed would have to be accounted for in the senate. The remark came to the ears of Sallustius Crispus. A partner in the imperial secrets — it was he who had forwarded the note to the tribune — he feared the charge might be fastened on himself, with the risks equally great whether he spoke the truth or lied. He therefore advised Livia not to publish the mysteries of the palace, the counsels of her friends, the services of the soldiery; and also to watch that Tiberius did not weaken the powers of the throne by referring everything and all things to the senate:— ‘It was a condition of sovereignty that the account balanced only if rendered to a single auditor.’

Tacitus wonders why Augustus would remove his own grandson to ease the way for his stepson. Tiberius’ motive was straightforward.

Nevertheless, there are interesting questions

1. Why does Tiberius act with confusion when the murder was reported to him as a fulfilment of his orders? Tiberius looks to have been confused by the actions?
2. if the order was not issued by Tiberius, did Sallustius Crispus act on his own initiative in ordering the death of a member of the imperial family?
3. Why was Tiberius’ proposed inquiry shelved?
4. How could Tacitus know what was said in these secret meetings? He even has a quote!

Look also at the first sentence. By describing it is the first crime of the regime (not of Tiberius), Tacitus makes reference to the many crimes that will follow. From the various line of his depiction, Tiberius and his regime are criminal.

The murder of Agrippa seems an inevitable consequence of the traumas which the imperial family suffered in the last years of the Augustan regime. The political in-fighting led to the exiles of many prominent individuals, including Julia, daughter of Augustus, and the grandchildren, Julia the Younger and Agrippa Postumus.  Agrippa could not be allowed to live in case he became a rallying point for opposition to Tiberius. The violent and difficult last years of Augustus claimed another victim.

But equally notably, the removal of Agrippa speaks of the insecurity of the regime and a knowledge that even in AD 14 Tiberius had many opponents who would happily see an alternative emperor. It seems likely that Tacitus was right: the survival of the regime required Agrippa’s murder whatever Tiberius’ finer feelings.

Accession and Accession Debate                Exile of Agrippa Postumus                      Germanicus