Agrippina the Younger exercised influence at the centre of the Julio-Claudian dynasty as the sister of Caligula, wife of Claudius and mother of Nero. Her public position rose with Caligula's accession in 37 CE, when he honoured his sisters prominently. Accused of involvement in a conspiracy, she was exiled in 39. Claudius recalled her after becoming emperor in 41, allowing her to rebuild her wealth, relationships and place within the imperial family.

Her marriage to Claudius in 49 required permission for a union between uncle and niece. She then worked to advance Nero, her son by an earlier marriage. Claudius adopted him in 50, placing him alongside the emperor's own son Britannicus as a possible successor. Agrippina helped secure the appointment of allies, including Seneca as Nero's tutor and Burrus as praetorian prefect. She received the title Augusta, and her image on coins and participation in ceremonial occasions displayed an unusually visible female authority.

When Claudius died in 54, Nero succeeded him with the support of the guard. Ancient writers accused Agrippina of poisoning her husband, but their accounts cannot establish the circumstances with certainty. Early in Nero's reign she appeared with him on coinage and received foreign delegations. Her power depended on dynastic status, access and alliances rather than on an office equivalent to the emperor's.

Relations with Nero deteriorated as he asserted independence and turned to other advisers. The removal of her supporters and restrictions on her access weakened her influence. In 59 Nero ordered her killing; the surviving narratives describe a failed attempt at sea followed by murder ashore, though details vary. Agrippina also wrote memoirs, now lost, that Tacitus used as a source. Her career reveals the opportunities available to an imperial woman through family and patronage, as well as the hostility such authority attracted from the men who recorded it.