Multiple choice According to historians, when did the Roman Empire officially begin? When Julius Caesar became dictator. When Augustus Caesar became emperor. When Marcus Aurelius became emperor. When Diocletian split the empire. Reveal answer Fill a bubble to check yourself B Correct answer Explanation Historians generally mark the official beginning of the Roman Empire in 27 BC, when Octavian was granted the title of Augustus by the Senate. This transition ended the Roman Republic and established Augustus as the first Roman Emperor.