The transition from Roman Republic to Empire occurred over several violent periods beginning with the Gracchus Brothers reforms sparking conflict, followed by the power struggle between Marius and Sulla, and culminating with Julius Caesar crossing the Rubicon which began a civil war allowing him to become dictator before being assassinated, leading to additional conflict between Mark Anthony and Octavian which Octavian ultimately won allowing him to become the first Roman emperor Augustus and begin the Pax Romana period of peace.