What is the dictionary definition for this idea/event?
Pax Romana (Latin for "Roman peace") was the long period of relative peace and minimal expansion by military force experienced by the Roman Empire in the 1st and 2nd centuries AD.
Who (give me precise people) started this idea/event?
The people that started this event was Augustus in 27 BC at the end of the Roman Republic and lasted until 180 AD to the death of Marcus Aurelius.
What were the reasons that this happened (previous philosophies/events that led up to this)?
List and describe the major events and people in this idea/event?
The Pax Romana started after Octavian (Augustus) defeated Mark Antony in the Battle of Actium. He became princeps, or "first citizen". Lacking a good precedent of successful one-man rule, Augustus created a junta of the greatest military magnates and stood as the front man. By binding together these leading magnates in a coalition, he eliminated the prospect of civil war. The Pax Romana was not immediate, despite the end of the civil wars, because fighting continued in Spain and in the Alps. Nevertheless, Augustus closed the Gates of Janus (the Roman ceremony to mark world Peace) three times first in 29 BC and again in 25 BC. At the time of the Ludi Saeculares in 17 BC the concept of Peace was publicized, and in 13 BC was proclaimed when Augustus and Agrippa jointly returned from pacifying the provinces. The Ara Pacis ceremony was no doubt part of this announcement.
Augustus faced a problem making peace an acceptable mode of life for the Romans, who had been at war with one power or another continuously for 200 years. Romans regarded peace not as an absence of war, but the rare situation that existed when all opponents had been beaten down and lost the ability to resist. Augustus' challenge was to persuade Romans that the prosperity they could achieve in the absence of warfare was better for the Empire than the potential wealth and honor acquired when fighting a risky war. Augustus succeeded by means of skillful propaganda. Subsequent emperors followed his lead, sometimes producing lavish ceremonies to close the Gates of Janus, issuing coins with Pax on the reverse, and patronizing literature extolling the benefits of the Pax Romana.
What countries/civilizations were affected most by this idea/event?
Rome was the country most effected by the Pax Romana.
What effects of this idea/event do we encounter today?
We do not encounter any effects of the Pax Romana today since it ended in 180 AD.