Augustus and Agrippa , AR Denarius, Rome Mint, 13BC (17mm, 3.32g, 4H).

Gaius Julius Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire. He reigned as the first Roman emperor from 27 BC until his death in AD 14.^[a] The reign of Augustus initiated an imperial cult, as well as an era of imperial peace (the Pax Romana or Pax Augusta) 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.

Octavian was born into an equestrian branch of the plebeian gens Octavia. His maternal great-uncle Julius Caesar was assassinated in 44 BC, and Octavian was named in Caesar's will as his adopted son and heir; as a result, he inherited Caesar's name, estate, and the loyalty of his legions. He, Mark Antony, and Marcus Lepidus formed the Second Triumvirate to defeat the assassins of Caesar. Following their victory at the Battle of Philippi (42 BC), the Triumvirate divided the Roman Republic among themselves and ruled as de facto dictators. The Triumvirate was eventually torn apart by the competing ambitions of its members; Lepidus was exiled in 36 BC, and Antony was defeated by Octavian at the Battle of Actium in 31 BC. Antony and his wife Cleopatra, the Ptolemaic queen of Egypt, killed themselves during Octavian's invasion of Egypt, which then became a Roman province.