Quick questions on Agrippina the Younger's historical context and family background: HSC Ancient History

Agrippina the Younger was born on 6 November AD 15 at the Roman military camp at Ara Ubiorum on the Rhine, where her father Germanicus was campaigning against the Germanic tribes after the Varian disaster of AD 9. The site was later renamed Colonia Claudia Ara Agrippinensium when Claudius founded a Roman colony there in her honour as Augusta. The modern city of Cologne preserves the name.

The dynasty had been founded by Augustus (Octavian) in 27 BC after his victory over Mark Antony at Actium in 31 BC. By Agrippina's birth in AD 15 the principate had been consolidated; Tiberius, Augustus's stepson and adopted heir, had succeeded the previous year.

Agrippina's lineage was the most distinguished available to any imperial wife.

The Republic had no formal political role for women. The Principate developed one informally, building on the late-Republican prominence of women like Cornelia, mother of the Gracchi.

The Augustan settlement (27 BC and 23 BC) had created a monarchy with Republican forms.

Augustus had created nine cohorts (later ten) of elite troops as his personal guard. Tiberius's prefect Sejanus had concentrated them in a single camp (Castra Praetoria) on the eastern edge of Rome in AD 23. The Guard had hailed Claudius emperor after Caligula's assassination in AD 41, in exchange for a donative of 15,000 sesterces per man (Suetonius, Claudius 10). The Guard would matter to Agrippina: Burrus, the prefect she secured for the Guard, was the instrument of Nero's accession.

Tacitus, Annals. Books 1 to 6 cover Tiberius (with frequent reference to the elder Agrippina); 11 to 12 cover the later reign of Claudius and Agrippina the Younger's marriage; 13 to 16 cover Nero. Tacitus is the dominant source.

Established the Principate. Granted his wife Livia the title Augusta in his will. His daughter Julia the Elder (by his second wife Scribonia) was Agrippina the Younger's great-grandmother.

Reigned during Agrippina the Younger's childhood and adolescence. Distrusted Germanicus; the elder Agrippina believed Tiberius had poisoned him in AD 19.

Agrippina the Younger's brother. The early years of his reign elevated his three sisters (Agrippina, Drusilla, Julia Livilla) to unprecedented public honours; the later years exiled them.

Agrippina's uncle (and from AD 49 her husband). Hailed emperor by the Praetorian Guard after Caligula's assassination.

Agrippina's son. The last Julio-Claudian.

Adopted son of Tiberius. Popular general of the Rhine and Eastern campaigns. Died at Antioch in suspicious circumstances; his widow blamed Tiberius and the governor Cnaeus Calpurnius Piso.

Granddaughter of Augustus through Julia the Elder and Marcus Agrippa. A political force in her own right. Tacitus (Annals 1 to 6) treats her as the moral antagonist of Tiberius.

The two elder brothers died in the purges of Sejanus (around AD 31). Caligula survived and ruled.