Pax Romana

The Pax Romana, Latin for "Roman Peace," describes a roughly two-century span in ancient Rome often called a golden age. This era was marked by intensified Roman imperialism, widespread stability, dominant power, territorial growth, and a general state of calm, though it did include internal uprisings and external conflicts such as the Roman–Persian wars. By tradition, the period began with Augustus's rise to power in 27 BC, when he established the Roman principate, and ended with the death of Marcus Aurelius in 180 AD, the last of the "Five Good Emperors."

During this time, the Roman Empire reached its largest territorial extent under Trajan in 117 AD. The population of the empire is thought to have peaked at around 70 million people, which made up about 33% of the global population at the time. After the Pax Romana, according to the historian Cassius Dio, the authoritarian rule of Commodus—followed by the Year of the Five Emperors and the Crisis of the Third Century—caused Rome to fall "from a kingdom of gold to one of iron and rust."

The Pax Romana is considered one of history's longest sustained periods of peace, though scholars debate its nature. Walter Goffart noted that the *Cambridge Ancient History* volume covering AD 70–192 is titled "The Imperial Peace," yet peace is scarce within its pages. Arthur M. Eckstein, however, argues that this era should be compared to the far more frequent warfare of the Roman Republic in the 3rd and 4th centuries BC. Eckstein also points out that the Pax Romana first emerged during the Republic and varied by region: Sicily after 210 BC, the Italian Peninsula after 200 BC, the Po Valley after 190 BC, most of Iberia after 133 BC, North Africa after 100 BC, and for longer stretches in the Greek East. Thomas F. Madden explains that the conventional start date of 27 BC avoids the civil wars of the 1st century BC; he sees the true origins in the 2nd century BC, after Rome had eliminated serious rivals and brought unprecedented peace and prosperity to its lands. Tim Cornell argues that the Pax Romana, meaning the absence of major interstate wars, began in the 2nd century BC, as the frequency of wars declined over the Republic's last two centuries.

The term *Pax Romana* first appears in a work by Seneca the Younger from AD 55. The concept has been highly influential, inspiring theories and attempts at imitation in later ages. Arnaldo Momigliano remarked that "Pax Romana is a simple formula for propaganda, but a difficult subject for research." For most historians, the period began when Octavian (Augustus) defeated Mark Antony and Cleopatra at the Battle of Actium on September 2, 31 BC, and became emperor. Lacking a precedent for successful one-man rule, Augustus formed a coalition of leading military magnates, acting as the front man. By uniting these powerful figures, he prevented civil war. The Pax Romana did not start immediately, as fighting continued in Hispania and the Alps. Still, Augustus closed the Gates of Janus—a ceremony signifying Rome was at peace—three times: first in 29 BC, again in 25 BC, and a third time, likely in 13 BC, when the Ara Pacis was commissioned (as argued by Inez Scott Ryberg in 1949 and Gaius Stern in 2006). The concept of peace was publicized during the Ludi Saeculares in 17 BC, and in 13 BC it was proclaimed when Augustus and Agrippa returned from pacifying Hispania and the Alps. The order to build the Ara Pacis was probably part of this announcement.

Romans viewed peace not as the absence of war, but as a rare condition achieved when all opponents were crushed and unable to resist. Augustus's challenge was to convince Romans that the prosperity of peacetime was better for the empire than the wealth and honor from risky wars. He succeeded through skillful propaganda. Later emperors followed his example, sometimes staging lavish ceremonies to close the Gates of Janus, minting coins with Pax on the reverse, and supporting literature that praised the benefits of the Pax Romana. After Augustus's death in AD 14, most successors continued his policies. The last five emperors of this era are known as the "Five Good Emperors."

Roman trade in the Mediterranean grew during the Pax Romana. Romans sailed east for silks, gems, onyx, and spices, earning large profits and raising incomes across the empire. Because the Pax Romana in the West overlapped with the Pax Sinica in the East under Han China, long-distance travel and trade across Eurasia were significantly stimulated.

The influence of the Pax Romana concept led historians to coin similar terms for other periods of relative peace, such as the Pax Americana, Pax Assyriaca, Pax Atomica, and Pax Britannica.