Final answer:
The Pax Romana is the term for the nearly 200 years of peace and prosperity that the Roman Empire enjoyed, beginning with Emperor Augustus and concluding with Marcus Aurelius.
Step-by-step explanation:
The term for the period of peace and prosperity in the Roman Empire that lasted nearly 200 years is known as the Pax Romana. This era of relative stability and wealth was initiated by Augustus, the first Roman Emperor, and lasted until the death of Marcus Aurelius. During the Pax Romana, the Roman Empire experienced its height in power, extending from the Atlantic coast of Spain all the way to Mesopotamia. The empire was secured with good roads, official protection from banditry, and a common trade language. Despite its splendor and dominance, the period also represented oppression and imperialism to many within its bounds.
The Pax Romana included three main imperial dynasties: the Julian dynasty, the Flavian dynasty, and the reign of the 'Five Good Emperors'. It was during the rule of Trajan in this period that the Roman Empire reached its greatest geographical extent. However, following this peak, the late Roman Empire faced increasing challenges leading to its eventual decline including the Crisis of the Third Century and the collapse of the Severan Dynasty.