Agrippina was at the forefront of the accession. Honours granted to Claudius were paralleled in honours given to Agrippina. She was to be accompanied by two lictors, as if she were a magistrate. She was made a priestess of her late husband’s cult. She was also given a military guard of Roman and German soldiers, for at least the early part of Nero’s reign.
She also appeared on coins alongside her son.
Initially, the imagery suggests that Agrippina was very much a partner in power and Dio suggests that she received embassies on behalf of Rome and her son (Dio, 61.3). Her influence was very public and we must assume that she and Nero believed that he benefited from his association and his obvious reliance upon her, very much as Claudius had done.
But matters changed quickly. When an Armenian delegation was presented to the emperor in AD 54, Agrippina was prevented from joining the emperor on the tribunal by Nero’s sudden descent (Dio, 61. 3; Tacitus, Annales 13.5). The tribunal was the place from which a magistrate did business. It is not clear whether Agrippina had sat at a tribunal before, either with or husband or her son, though if she had, no historian has recorded the fact. Kepping her from the tribunal maintained some of the boundaries of gender in Roman public life.
In 55, Pallas was forced into retirement (Tacitus, Annales 13. 14). He was a long-time ally of the emperor’s mother. Then, her bodyguard was withdrawn (Dio, 61. 8; Suetonius, Nero 34). This last was a shift in the representation of Agrippina: no longer was she the partner in power.
It seems that in AD 55, Poppaea Sabina caught the eye of the emperor (Tacitus, Annales 13. 44–5; Dio, 61. 11). She was engaged in a love affair with Otho, the future emperor and a close friend of Nero. After Otho married her, he began to boast of the qualities of his wife to Nero. The story feels very literary: boasting of a wife before a tyrant was unlikely to end well. There is also a suggestion that Otho was pimping his wife. Again, secrets of the imperial bedroom seem to have been subject to novelistic inventions.
Anyhow, Nero became enamoured. Otho was packed off to be governor of Lusitania (suggesting that if this was a strategy, it misfired badly), leaving Poppaea free in Rome. But Nero was not. Nero was married to Octavia. She would hardly have been naive enough to expect sexual fidelity: Nero had a long-lasting liaison with a freedwoman, Acte, but Poppaea wanted more than being the emperor’s mistress.
For Romans, divorce was a straightforward matter: Poppaea and Nero faced none of the theological problems that were to beset Henry VIII and Anne Boleyn a millenniumand a half later. But marriages were political and it follows that divorces were similarly so.
The Julio-Claudians were dynastic in the marriages, using them to knit the various lines of the family together. This was the reason why Agrippina herself had been such a good choice for Claudius and why Nero had been married to Octavia in the first instance. Poppaea had not the same value as a wife. It seems possible, as our sources suggest, that Agrippina and Burrus supported Octavia. Agrippina had carefully engineered the alliance. Britannicus had already been removed, but one suspects that there had been a political cost to the murder. A deserted Octavia was likely to be a focus of sympathy and resentment, as Agrippina’s mother had been. Any future husband would be a potential heir to the throne. Getting rid of Octavia would make her a victim, and Nero seem a tyrant. And what was the benefit? This was family politics in its toughest form: it did not matter, really, whether Nero slept with half the women or men of the court. It did matter to whom he was married.