Agrippina the Elder in the context of "Agrippa Postumus"

Gaius Caesar Augustus Germanicus (31 August 12 – 24 January 41), also called Gaius and Caligula (/kəˈlɪɡjʊlə/), was Roman emperor from AD 37 until his assassination in 41. He was the son of the Roman general Germanicus and Augustus' granddaughter Agrippina the Elder, members of the first ruling family of the Roman Empire. He was born two years before Tiberius became emperor. Gaius accompanied his father, mother and siblings on campaign in Germania, at little more than four or five years old. He had been named after Gaius Julius Caesar, but his father's soldiers affectionately nicknamed him "Caligula" ('little boot').

Germanicus died in Antioch in AD 19, and Agrippina returned with her six children to Rome, where she became entangled in a bitter feud with Emperor Tiberius, who was Germanicus' biological uncle and adoptive father. The conflict eventually led to the destruction of her family, with Caligula as the sole male survivor. In 26, Tiberius withdrew from public life to the island of Capri, and in 31, Caligula joined him there. Tiberius died in 37, and Caligula succeeded him as emperor, at the age of 24.

Germanicus Julius Caesar (24 May 15 BC – 10 October AD 19) was a Roman general and politician most famously known for his campaigns against Arminius in Germania. The son of Nero Claudius Drusus and Antonia the Younger, Germanicus was born into an influential branch of the patrician gens Claudia. The agnomen Germanicus was added to his full name in 9 BC when it was posthumously awarded to his father in honor of his victories in Germania. In AD 4 he was adopted by his paternal uncle Tiberius, himself the stepson and heir of Germanicus' great-uncle Augustus; ten years later, Tiberius succeeded Augustus as Roman emperor. As a result of his adoption, Germanicus became an official member of the gens Julia, another prominent family, to which he was related on his mother's side. His connection to the Julii Caesares was further consolidated through a marriage between him and Agrippina the Elder, a granddaughter of Augustus. He was also the father of Caligula, the maternal grandfather of Nero, and the older brother of Claudius.

During the reign of Augustus, Germanicus enjoyed an accelerated political career, entering the office of quaestor five years before the legal age in AD 7. He held that office until AD 9 where he was made praetor after the Pannonian war, and was elected consul for the first time in AD 12. The year after, he was made proconsul of Germania Inferior, Germania Superior, and all of Gaul. From there he commanded eight legions, about one-third of the entire Roman army at the time, which he led against the Germanic tribes in his campaigns from AD 14 to 16. He avenged the Roman Empire's defeat in the Teutoburg Forest and retrieved two of the three legionary eagles that had been lost during the battle. In AD 17, he returned to Rome, where he received a triumph before leaving to reorganize the provinces of Asia Minor, whereby he incorporated the provinces of Cappadocia and Commagene in AD 18.

Julia Agrippina (6 November AD 15 – 23 March AD 59), also referred to as Agrippina the Younger, was Roman empress from AD 49 to 54, the fourth wife and niece of emperor Claudius, and the mother of Nero.

Agrippina was one of the most prominent women in the Julio-Claudian dynasty. She was the great-granddaughter of Augustus (the first Roman emperor) and the daughter of the Roman general Germanicus and Agrippina the Elder. Her father, Germanicus, was the nephew and heir apparent of the second emperor, Tiberius. Agrippina's brother Caligula became emperor in AD 37. After Caligula was assassinated in AD 41, Germanicus' brother Claudius took the throne. Agrippina married Claudius in AD 49.