Gaius Julius Caesar Augustus (23 September 63 BC – 19 August AD 14) was the first emperor of the Roman Empire, which he ruled alone from 31 BC until his death in AD 14.

Born Gaius Octavius Thurinus, he was adopted by his great-uncle Gaius Julius Caesar in 44 BC, and between then and 31 BC was officially named Gaius Julius Caesar. The young Octavius came into his inheritance after Caesar's assassination in 44 BC. In 43 BC, Octavian joined forces with Mark Antony and Marcus Aemilius Lepidus in a military dictatorship known as the Second Triumvirate

The rule of Augustus initiated an era of relative peace known as the Pax Romana, or Roman peace. Despite continuous frontier wars, and one year-long civil war over the imperial succession, the Mediterranean world remained at peace for more than two centuries. Augustus expanded the Roman Empire, secured its boundaries with client states, and made peace with Parthia through diplomacy. He reformed the Roman system of taxation, developed networks of roads with an official courier system, established a standing army (and a small navy), established the Praetorian Guard, and created official police and fire-fighting forces for Rome. Much of the city was rebuilt under Augustus; and he wrote a record of his own accomplishments, known as the Res Gestae Divi Augusti, which has survived. Upon his death in AD 14, Augustus was declared a god by the Senate, to be worshipped by the Romans.^[4] His names Augustus and Caesar were adopted by every subsequent emperor, and the month of Sextilis was officially renamed August in his honour