Gaius Caesar, Roman consul and grandson of Augustus (born 20 BC)

The 0s began on January 1, AD 1 and ended on December 31, AD 9, covering the first nine years of the Common Era.

Gaius Caesar was a grandson and heir to the throne of Roman emperor Augustus, alongside his younger brother Lucius Caesar. Although he was born to Marcus Vipsanius Agrippa and Julia, Augustus' only daughter, Gaius and Lucius were raised by their grandfather as his adopted sons and joint-heirs. He experienced an accelerated political career befitting a member of the Julio-Claudian dynasty, with the Roman Senate allowing him to advance his career without first holding a quaestorship or praetorship, offices that ordinary senators were required to hold as part of the cursus honorum.

The consuls were the two highest elected public officials of the Roman Republic. Romans considered the consulship the second-highest level of the cursus honorum—an ascending sequence of public offices to which politicians aspired—after that of the censor, which was reserved for former consuls. Each year, the centuriate assembly elected two consuls to serve jointly for a one-year term. The consuls alternated each month holding fasces when both were in Rome. A consul's imperium extended over Rome and all its provinces.

Gaius Julius Caesar Augustus, also known as Octavian, was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult and an era of imperial peace in which the Roman world was largely free of armed conflict. The Principate system of government was established during his reign and lasted until the Crisis of the Third Century.