This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Most traditions represented in this atlas have developed their own doctrine addressing when, if ever, violence is religiously justified, and the doctrines differ sharply from one another. Christian just war theory, built by Augustine and substantially refined by Thomas Aquinas, sets out conditions such as legitimate authority, just cause and right intention that a war must meet to be morally permitted. Islamic tradition distinguishes multiple senses of jihad, ranging from an inward moral struggle to an armed struggle bound by its own legal conditions, a distinction Islamic scholars themselves have long insisted on maintaining. The Bhagavad Gita frames its central teaching as an answer to Arjuna's reluctance to fight his own kin, developing the concept of dharma yuddha, a war fought as duty. Sikh tradition formalized its own concept of dharm yudh, righteous war, particularly from the founding of the Khalsa under Guru Gobind Singh.
Comparative method separates a conflict's religious framing from its other causes rather than accepting either a purely religious or a purely secular account on faith. Historians studying the medieval Crusades document mixed motives, religious, political and economic together, rather than treating religious justification alone as sufficient explanation. The First World War is a documented case of the same caution applied to a modern conflict: national churches on multiple sides framed the same war in religious terms simultaneously, which historians read as evidence about how each side understood and justified the conflict to itself rather than as evidence that the war was fundamentally religious in cause.
The field also studies how a conflict is remembered in religious terms well after the fact, separately from how contemporaries understood it at the time. The word crusade itself was applied retrospectively to expand what counted as a crusading conflict beyond the medieval campaigns to Jerusalem, and later movements and even later wars have been described using crusade language that was not necessarily used, or used in the same way, by participants at the time; tracking that gap between contemporary framing and later retrospective framing is itself part of what the comparative study of religious conflict does.