D. political instability.
The Pax Romana also perceived as Roman Peace was a time of relevant union and security beyond the Roman Empire which continued for over 200 years, commencing with the reign of Augustus (27 BCE - 14 CE).
During the survival of both the Roman Republic and Empire, the boundaries of Rome continuously extended. Most of the chroniclers accept that the Pax Romana concluded in the year 235 C.E. with the commencement of a time recognized as the 'Crisis of the Third Century,' which originated with the murder of Roman Emperor Severus Alexander by his own companies.