From 96 ad till 180 ad the Roman Empire experienced a period of peace called the Pax Romana. This 84-year period saw unprecedented peace and economic prosperity throughout the Empire, which spanned from England in the north to Morocco in the south and Iraq in the east. During the Pax Romana (latin for Roman peace), the Roman Empire reached its peak in terms of land area, and its population swelled to an estimated 70 million people.
The period witnessed considerable expansion of the empire, from northern Britain to Dacia and to Arabia and Mesopotamia. The empire was consolidated. Defenses were built especially by Hadrian (famous for his wall) and an uniform political system covered the entire empire.
Five good emperors
At the heart of this Pax Romana were five good emperors Nerva reigned ad 96–98), Trajan (98–117), Hadrian (117–138), Antoninus Pius (138–161) and Marcus Aurelius (161-180)
It was not a bloodline; Nerva was raised to the principate by the assassins of Domitian, and the others were successively adopted heirs, each only distantly related to his predecessor if at all. The last two—Antoninus Pius and Marcus Aurelius—are often called the Antonines, though the term Antonine is sometimes extended also to the co emperors Lucius Verus (adopted heir of Antoninus Pius) and Commodus (son of Marcus Aurelius).
The wars along the Danube and in the East that marked the last years of Marcus Aurelius’s rule were caused by the massive movement of populations outside the empire that was to lead to the “barbarian invasions” of later centuries and the empire’s eventual collapse.