Final answer:
The 'Five Good Emperors' were Roman rulers from 96 to 180 CE selected for their merit, under whom the empire achieved its greatest expansion and prosperity.
Step-by-step explanation:
The Period of the Five Good Emperors
The period known as the reign of the Five Good Emperors refers to the era in Roman history from 96 to 180 CE. During this time, the Roman Empire was governed by a series of rulers who were selected for their competence rather than by hereditary succession. This group included Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius. Under their leadership, particularly during Trajan's rule, the empire reached its greatest territorial expansion and prospered in peace and stability, known as the Pax Romana. Unfortunately, this era came to an end with the death of Marcus Aurelius, and the subsequent reigns of the Severan dynasty were marked by instability leading to the eventual decline of the Roman Empire.