According to Michael Walzer, the Just War Theory essentially provides a basis for nations to determine whether their reasons for going to war are justified. The theory goes even further to allow citizens to influence how governments act when they go to war, particularly in terms of conquest and defeat. The three primary aspects of Walzer’s theory include: Justice of War, Justice in War, and Justice after War. Each of these three aspects can be seen played out within the spread of Islam, the Coronation of Charlemagne as Emperor, and the early empires.

The notion of Justice of War refers to the idea that war can be justified when there is aggression to resist an attack, aid a victim of aggression, or stop a massacre. The spread of Islam is one example of where we see this notion used as a justification for going to war. Since the ultimate goal of Islam is peace, we can argue that Muhammad’s conquest of the city of Mecca during the early Islamic movement was just. The tribal leaders had caused an uproar over Muhammad’s teachings, and he returned to Mecca, after being driven out, to deliver the people from oppression.

Pope Leo III crowned Charlemagne as Emperor of Rome at a time when the Holy See was experiencing turmoil, because many believed the Pope should be of noble birth, and Charlemagne was interested in uniting the Germanic tribes. However, Charlemagne’s coronation meant military protection for the Holy See, especially since the Roman Catholic Church did not have an army and there was an attempt to assassinate the Pope. This protection is likely an example of Justice in War because it sheds light on noncombatant immunity.

The Assyrian deportations are a prime example of Justice After War because it reflects an empire’s responsibility to the conquered or defeated people. The Babylonian King offered the Assyrians the chance to relocate after seizing their land, particularly if they did not want to assimilate to the new customs and culture. What’s most interesting about this offer is how they could have otherwise been killed for refusing to surrender their identity and pay homage to the new king.

Throughout the early empires and medieval period we have seen numerous conquests, the rise and fall of power elites, and transitions to new cultures and identities. The Just War Theory has played an important role in shaping how people have dealt and continue to deal with each of these occurrences. Islam is a major religion today because of how it has responded to aggression towards Muhammad’s teachings, which epitomizes the notion of Justice of War. The purposeful intentions of Pope Leo III’s coronation of Charlemagne as Emperor of Rome, securing military protection of the Holy See, set the course for how we treat noncombatants during war. Lastly, as early as the Assyrian deportations in the late 8th and 7th centuries BCE, nations have been deciding on the best way to help citizens recover from war.