Religious war

A religious war is a conflict primarily caused or justified by differences in religious beliefs. These are sometimes called "holy wars," or *bellum sacrum*. In a holy war, religious leaders must authorize the fighting. The soldiers must also be pious. However, a "religious war" is a broader term. It can include conflicts where a worldly leader uses religion to justify a war.

This distinction is important for historians. It helps them separate true religious movements from political ones.

Understanding these wars requires looking at the mechanism of justification. Leaders often use religious language to gain public support for a war. This process is called legitimization. A leader might claim a war is necessary for their faith. However, they may have an "ulterior motive." This means they have a hidden reason for fighting. These reasons are often secular, meaning they are not religious.

For example, a leader might want more land or political power. They use religion as a cover for these underlying goals.

Conflicts often involve multiple, overlapping stages or causes. A single war can be both a war of succession and a religious war. A war of succession happens when people fight over who will take a throne. This occurred during the French Wars of Religion. During the Succession of Henry IV of France, claimants to the throne represented different religions. Similar patterns appeared in the Hessian War and the War of the Jülich Succession. Even the Jacobite risings in Great Britain and Ireland involved these overlapping factors.

In these cases, religion and politics are tied together.

Historians have studied the frequency of these conflicts to find patterns. The *Encyclopedia of Wars* recorded 1,763 known historical conflicts. Only 121 of these, or about 6.87%, had religion as their primary cause. This suggests that religion is not the most common driver of war. Most wars are driven by territorial, ethnic, or economic concerns. Matthew White’s research also shows this trend. He found that religion was the primary cause of only 11 of the 100 deadliest atrocities.

This data helps prevent the oversimplification of history.

The very definition of "religion" is a complex part of this study. The concept of religion as a modern Western idea is debated. Theologian William T. Cavanaugh argues that the term is a recent invention. In the 17th century, the English language began using "religion" as an abstraction. This happened during the Protestant Reformation and the age of exploration. Before this, the word *religio* in Latin meant a virtue of worship. It did not mean a set of doctrines or a source of knowledge.

This shows how definitions change over time.

Different cultures have used different terms for these concepts. In ancient times, many people saw religion and law as the same thing. The Sanskrit word *dharma* is often translated as religion, but it also means law. In the Quran, the Arabic word for religion was often translated as "law" until the mid-17th century. Japan provides another example of this shift. Japan had no specific word for religion until 1853. This changed when American warships arrived and demanded freedom of religion.

This forced Japan to adopt Western ideas about faith.

Modern conflicts often show how religion and ethnicity overlap. In Northern Ireland, "The Troubles" are often called a religious war. This involves Catholic and Protestant factions. However, scholars like McGarry and O'Leary argue it was actually about national identity. The religious labels became shorthand for two different cultures. Similarly, in conflicts in Syria, Iraq, or Israel and Palestine, religious elements are present. Some observers call this religious extremism. Others argue that ethnic animosities are the true drivers.

This highlights why historians must be careful with labels.