Which emperor began the Pax Romana (Roman Peace)? (r. 27 BC - 14 AD)

Augustus (r. 27 BC–AD 14) began the Pax Romana by ending Rome’s civil wars and founding the Principate. Through the settlements of 27 and 23 BC, he kept republican forms while holding real power, professionalized the army, created the Praetorian Guard, reformed taxation and provinces, and built roads and cities. He even closed the Temple of Janus, a ceremonial sign that Rome was at peace. These measures launched roughly two centuries of relative stability and prosperity across the empire. His successors maintained what he started: Tiberius inherited the stable system, Claudius expanded it (e.g., Britain), and Nero’s reign showed how fragile peace could be. Memory tip: A is for Augustus and for the “Age” of peace—he “augmented” Rome’s power and then kept it calm.