Augustus (Latin: Imperator Caesar Divi Filius Augustus, 23 September 63 BC – 19 August 14 AD) was the founder and first emperor (officially known as princeps civitatis, ‘first citizen’) of the Roman Empire. His rule is generally considered to have started with his assumption of the title augustus (from which his name in history is derived), lasting from 27 BC until his death in 14 AD.
Born as Gaius Octavius, he was adopted posthumously by Julius Caesar at the age of 18 in 44 BC. Known to historians as Octavian and to his contemporaries as Caesar during this time, he went on to form the so-called Second Triumvirate with Julius Caesar’s former officers Lepidus and Marc Antony. Following the defeat of Caesar’s assassins at Phillipi in 42 BC, he ousted Lepidus and defeated Antony and his lover Cleopatra at the Battle of Actium in 31 BC. He then restored the outward facade of the Roman Republic but ruled as de facto monarch from 27 BC and is known to historians as Augustus from this time. His reign was spent consolidating Rome’s vast empire through renewed expansion, absorption of vassal states and building the constitutional framework of the so-called Principate. Thus began the first phase of the Roman Empire and the Pax Romana, the longest recorded period of peace in Europe, the Middle East and North Africa.