The Romans expanded their domains from Anatolia in the east to Britannia in the west. In 44 BC as it approached its height, its dictator Julius Caesar was murdered by senators in an attempt to restore the Republic. In the ensuing turmoil, Octavian (ruled as Augustus; and as "divi filius", or Son of God, as Julius had adopted him as an heir) usurped the reins of power and fought the Roman Senate. While proclaiming the rebirth of the Republic, he had ushered in the transfer of the Roman state from a republic to an empire, the Roman Empire, which lasted for more than four centuries until the fall of the Western Roman Empire.