Religion and Warfare

Religion, inseparable from warfare throughout human history, has changed in significance over time, between contemporary cultures, or even within a nation or culture.


Religion, inseparable from warfare throughout human history, has changed in significance over time, between contemporary cultures, or even within a nation or culture. War has at times been a ritual process of religious significance, without any competition between dogmas or beliefs. Religion has been a source of inspiration to soldiers, without war having a particular religious purpose. In certain periods, religious conversion or competition has become the very reason for wars to be fought.Religion and warfareReligion and warfare


As wars are fought by human beings, who are often motivated by religious beliefs, religion can impact warfare as either an arbiter or actual cause for taking up arms. Many wars have been fought, and continue to be fought, in the name of religion, to impose a revealed truth or to resist encroachment.

History of Religion and Warfare

Ancient World

Ancient warfare was religious in nature. Peoples, nations, or empires generally had their own tribal or national gods, presumed to fight for their devoted worshippers. It was rare for any conqueror to seek mass conversion from one faith to another. Worship of the suzerain’s gods might be demanded as an act of submission or to promote imperial unity, but practice of preconquest cults was generally not questioned. The aid of lesser deities, worshiped by conquered subjects, might even be enlisted at times. Alternatively, a conquered people might transfer loyalty to the victor’s gods, which had proved to be the more powerful deities. Ancient cultures did not question the existence of one another’s gods but competed for favor and power of any god available.

The major exception was the twelve tribes of Israel;twelve tribesIsrael and JudahJudah, particularly Judah. The foundation of JudaismJudaism was a covenant with a single omnipotent God, gods of other nations being “the work of men’s hands.” Jewish judges, kings, and priests did not seek to bring other peoples into their covenant, as God’s chosen people, but proclaimed that Israel’s God was the sole ruler and creator of the universe. Military victory was considered evidence of God’s intervening to support his faithful chosen. Defeat, in contrast to many neighboring cultures, was not taken to mean that Israel’s god had proved weaker than rival gods. It was God’s punishment on Israel’s people for failing to live up to their obligations under the covenant. The ZoroastrianismZoroastrian faith of successive Persian dynasties, including the Achaemenids, Parthians, and Sāsānians, came closest to playing a similar role, which may have made Persian monarchs amenable to supporting renewal of Judaism and rebuilding of the Temple in Jerusalem, after the Babylonian Exile.

In most of the American continents, ancient warfare, endemic on a low-intensity scale, had less religious character, except for that of the AztecsAztecs and MayaMaya. War in both cultures was a sacred duty to the gods, in itself a ritual of worship. Wars also provided prisoners, who could be sacrificed to the gods. Aztec and Mayan warfare also consolidated smaller states and cities under the rule of ever larger empires.

Aryan invaders of the Indian subcontinent celebrated war in their sacred epics, particularly praising “the all out-stripping chariot wheel,” which conquered the previous inhabitants, destroying the Harrapān civilization in the Indus Valley. Division of the population into hereditary varna and jats was an essential part of the Hinduism Hindu religion, including a warrior varna, the Kshatriya Kshatriya. The conquered population, variously known as Dravidian, “untouchables,” or in recent times Dalit, was deemed ritually unclean in Hindu cosmology. Although Buddhism Buddhism was by origin a pacifist faith, arising later in the same region, that did not prevent kingdoms that adopted it as official religion from engaging in war.

Christianity in the Christianity;Roman EmpireRoman Empire, prior to the accession of Constantine, was largely a pacifist faith. Christians;soldiersChristians often refused military service. Not only were officers and soldiers required to worship Caesar, but also military service was deemed to violate the gospel of reconciliation. Saint Maximilian, SaintMaximilian, SaintMaximilian (274-295 c.e.) wrote, “You can cut off my head, but I will not be a soldier of this world, for I am a soldier of Christ. . . .” OrigenOrigenOrigen (c. 185-c. 254 c.e.) wrote that “we no longer take sword against a nation, nor do we learn any more to make war, having become sons of peace for the sake of Jesus, who is our commander.”

There is evidence of Christians serving in the Roman armies after 170 c.e., but many served in police or diplomatic functions rather than in battle. After 416 c.e., only Christians were permitted to serve as soldiers in the Roman army–Christianity having become the empire’s official religion. AmbroseAmbrose (bishop of Milan)Ambrose (bishop of Milan, 374-397 c.e.) and Augustine (bishop of North Africa, 395-430 c.e.) provided the theology of the “Just war”[Just war]“just war.” The features of a just war included just cause, proper authority, good intentions, and probability of success.

Medieval World

Christianity and Islam introduced the first wars motivated by advance of religious doctrine. Sāsānians[Sasanians]Sāsānian rulers of Persia at times considered the loyalty of Christians within their empire to be suspect, once the rival Roman and Byzantine empires adopted it as official imperial faith. A distinctly organized Christian hierarchy, particularly adhering to the Nestorian heresyNestorian heresy, satisfied the demands of Persian patriotism. Kingdoms and empires professing either Christianity or Islam fought over political, religious, financial, and cultural disputes during several centuries. As each religion fragmented into competing schools or sects, internecine warfare against perceived heresies became a recurrent feature of both Christian and Islamic cultures.

Initially disfavored or persecuted by the Roman emperors, Christianity achieved imperial recognition, and then status as official religion, between the reigns of Constantine the Great (r. 312-337) and Theodosius the Great (r. 379-395). Open state Christians;persecutionpersecution of non-Christians, and of Christians adhering to doctrines considered heresy, became well established in Theodosius’s reign. Persecution of Jews;persecutionJewish communities made the Jews into enthusiastic allies of Persian armies, then of the new Arabic invaders, bringing Islam to the gates of Jerusalem.

Islam Islam;attitudes toward warwas first introduced to communities outside the Arabian Peninsula by wars of conquest, which established the Umayyad caliphate, and its successor, the ՙAbbāsid caliphate. In the second sura, the Qur՚ān[Quran];on war[war]Qur՚ān enjoins believers to fight against unbelievers “until idolatry is no more and al-Lah’s religion reigns supreme,” but also that “There shall be no compulsion in religion.” Both injunctions were reflected in the subsequent conquest.

A relatively small army, inspired by Islam, based on the temporary political unification of the Arabian Peninsula, fell upon both the Byzantine and Persian empires at an opportune moment. The two long-dominant empires had exhausted themselves with thirty years of warfare. Each had burned the other’s temples, including the fire temple near Ganzak and the Church of the Resurrection in Jerusalem. Persecution of Monophysite ChristiansMonophysite Christians;MonophysitesChristians, as well as Jews, further weakened the loyalty of Byzantine subjects. Fewer than twenty thousand soldiers of the Muslim umma conquered all of Persia, as well as Syria and Egypt. At first, the Muslim community was more interested in collecting the jizya, a tax on unbelievers, than converting the conquered to Islam. Armies were kept in garrisons, separate from the existing cities. Conquered peoples practicing pagan or polytheistic traditions were likely to be offered a choice of conversion or death, while Christians and Jews were free to practice their faith.

Christianity in Western Europe survived the fall of the Roman Empire by conversion of the invading Germanic tribesGermanic peoples, who initially worshiped a Teutonic tribesTeutonic pantheon analogous to those of the pre-Christian Greeks and Romans. Many tribes, including the VisigothsVisigoths, adopted the ArianismArian heresy. Conversion of a king, and therefore an entire people, was often inspired by desire for victory in battle. Constantine the Great;conversion to ChristianityConstantine’s set the example; he adopted Christianity before his 312 c.e. victory at Rome’s Milvian Bridge, Battle of (312 c.e.)Milvian bridge. Clovis;conversion to ChristianityChlodowech (Clovis), king of the Franks, adopted Roman Christianity in 496 during a difficult battle with the Alamanni. His subsequent conquest of the Visigothic kingdom, north of the Pyrenees, marked a triumph of Rome over Arianism.

Godfrey of Bouillon, holding a poleax. Leader of the First Crusade in 1095, he became king of Jerusalem.

Religiously motivated wars known as the CrusadesCrusades began more than four and a half centuries after the establishment of the Islamic caliphate. Before 1000 c.e., the ՙAbbāsid caliphs, leaders of the Sunni MuslimsSunni branch of Islam, had fallen under the rule of Shia IslamShīՙite princes, while the Shīՙite Fāṭimids had established a rival caliphate in Egypt. By the later 1050’s, Turkish armies were clashing with Byzantine armies, which had taken advantage of the weakened caliphate to regain Tarsus, Antioch, and parts of northern Syria. In the 1060’s and 1070’s, Turkish armies, nominally acting in the name of the ՙAbbāsid caliphs, established a sultanate ruling Iraq, Iran, and parts of Syria, restoring Sunni ascension. Between 1074 and 1798, Western Europe generated a series of Crusades against the rising Ottoman Turkish Empire.

One feature of theCrusader orderscrusades was the formation of professed religious orders dedicated to military purposes. Previously, qualified laymen were considered to have a moral obligation to bear arms in defense of their faith, or specifically at the direction of the Roman church. However, when theKnights TemplarKnights Templar (1118-1119) and the Knights of Saint John of JerusalemKnights HospitallerOrder of the Hospital of Saint John in Jerusalem (1163-1206) became military orders, communities devoted to prayer and service became explicitly institutions of warfare. The notion that the vocation of churchmen denied them the use of force was largely abandoned. The Teutonic KnightsTeutonic Knights, established in 1198, followed a similar pattern.

Modern World

One demarcation of the medieval from the modern world, at least in western and central Europe, was the ReformationProtestantsProtestant Reformation. Following the Council of Trent (1545-1547)Council of Trent (1545-1547), Roman popes sought to suppress the Protestant heresy but also fought to reduce the influence of the Habsburg emperorsHabsburg emperors in Italy. While Holy Roman Emperor Charles VCharles V (Holy Roman Emperor)Charles V fought Protestant German princes from 1531 to 1555, his French (Roman Catholic) rivals often allied with the Protestants and also with (Muslim) corsairs from North Africa. Protestant faith inspired British military rivalry with Spain, culminating in defeat of the Spanish Armada (1588)Spanish Armada in 1588 and Dutch independence from Spanish Habsburg rule. In the 1540’s, England avoided bankruptcy by funding two-thirds of its military expenses from the sale of confiscated church lands. From 1618 to 1648, a period known as the Thirty Years’ War (1618-1648);religious vs. political impetusThirty Years’ War entangled the causes of Protestant religion and German liberty with the national and dynastic aspirations of Sweden, Denmark, France, the Holy Roman Emperor, Habsburg Austria, the Dutch Republic, and Spain.

Since 1700, religion has seldom been the motivator for wars, but it has commonly served as an ideological rationale. The American War of Independence was framed, in part, as an “Appeal to Heaven” from the rule of British monarch George III. Expansion of European colonial empires, in the Americas, Africa, and Asia, was given a veneer of moral purpose by calls to spread the Gospel to the heathen of those continents. Armies, governments, and civilians of almost any belligerent power have invoked prayers for victory and divine protection for those serving in the armed forces. In a world dominated by monotheistic faiths, this means, as Abraham Lincoln said in his second inaugural address, that both sides generally pray to the some God, who cannot answer the prayers of both, and may not answer the prayers of either.

An American Bible Society poster designed to solicit public support for a program of providing World War I servicemen with copies of the New Testament.

(Library of Congress)

Most modern armies make extensive provision for Chaplainschaplains to serve the spiritual needs of both enlisted men and women, and officers. Serving as officers in a military chain of command, chaplains are expected to maintain troop morale and serve the assigned military mission, as well as minister to individual soldiers. While some nations have emphasized a single national church in military chaplaincy, a diversity of faiths increasingly requires a variety of chaplains. The United States, with its variety of immigrants, is a model, but Britain has soldiers from dissenting Protestant sects, and a Roman Catholic minority, while many European countries have significant Islamic populations. Germany has established Protestant and Roman Catholic regions, and Latin America has a growing number of evangelical Protestant converts.

A prominent feature of religion in the modern world has been the rise of Pacifismpacifism in direct opposition to warfare in general. The philosophical basis of pacifism is not modern. Pacifism was never a practical political option, when any valley or city was in constant danger of being invaded by the nearest rival feudal lord, king, or imperial army, for any reason or no reason. The development of large, stable nation-states, with civilian control of the military and periods of substantial peace in parts of the world, gave pacifism a more plausible context. The sheer volume of slaughter in World War I, and the imbalance of colonial wars pitting machine guns against spears, gave pacifism additional moral force. The prospect of worldwide annihilation in an exchange of nuclear weapons gave ominous practical significance to the movement.

Early Christian writers Justin Martyr, Tertullian, Origen, Maximilian, Hippolytus, and Martin of Tours all denounced participation in war as inconsistent with the promise of Christianity, as did Pelagius. The order founded and named after Saint Francis of Assisi was in part pacifist but did not oppose the contemporary Crusades or demand pacifism of the leaders of the Roman church. Humanists such as Thomas More and Desiderius Erasmus also provided some precedent for pacifist thinking, but More, for example, served as chancellor in England, and Erasmus served the Counter-Reformation. Modern religious denominations opposed to war include the Society of Friends (Quakers), Church of the Brethren, and Seventh-day Adventists–but individual members of these churches have served in the military. Among the religiously motivated pacifist organizations of the twentieth century are the Fellowship of Reconciliation, the American Friends Service Committee, the Catholic Worker Movement, and the Catholic Peace Fellowship.Religion and warfare

Books and Articles

  • Barber, John. The Road from Eden: Studies in Christianity and Culture. Bethesda, Md.: Academica Press, 2008. A study of the influence of Reform Theology on Western culture, including warfare.
  • Fahey, Joseph J. War and the Christian Conscience. Maryknoll, N.Y.: Orbis Books, 2005. Presents a scenario in which the U.S. draft is reinstated. Examines the resulting moral and ethical decisions weighed by a female student called for military duty, from four historical perspectives: pacifism/nonviolence, just/limited war, total/holy war, and global citizenship.
  • Nolan, Cathal J. The Age of Wars of Religion, 1000-1650: An Encyclopedia of Global Warfare and Civilization. Westport, Conn.: Greenwood Press, 2006. More than three thousand entries in one thousand pages cover religion and warfare from a global perspective.
  • Parker, Geoffrey. The Thirty Years’ War. 2d ed. New York: Barnes and Noble, 1993. An update of a classic work that synthesizes the most important scholarship on the war that has been called Europe’s civil war, from politics and major figures to the warfare itself. Maps, chronology, genealogies, and index.
  • Randsborg, Klavs. Hjortspring: Warfare and Sacrifice in Early Europe. Oakville, Conn.: Aarhus University Press, 1995. Examines the ancient Scandinavian ship Hjortspring as an artifact of a defeated raid from the Hamburg region. Looks at this archaological treasure in the context of European pagan religions and warfare, as well as modern nationalism and archaeological theory.
  • Rao, Aparna, Michael Bollig, and Monika Böck, eds. The Practice of War: Production, Reproduction, and Communication of Armed Violence. Oxford, England: Berghahn Books, 2007. Examines warfare from the perspective of ethnographry and anthropology: “The fact is that war comes in many guises and its effects continue to be felt long after peace is proclaimed. . . . It is only over the long view that one can begin to see the commonalities that emerge from the different forms of conflict and can begin to generalize.”
  • Richardson, Glenn. Renaissance Monarchy: The Reigns of Henry VIII, Francis I, and Charles V. New York: Oxford University Press, 2002. Compares the most important Western leaders of the Renaissance while asking the question of why warfare was endemic in early sixteenth century Europe.
  • Riley-Smith, Jonathan. The Crusades: A Short History. New Haven, Conn.: Yale University Press, 1987. A classic, hailed as the most authoritative work on the Crusades, as well as counterpart movements in the modern world. Excellent starting point for students.
  • Soustelle, Jacques. Daily Life of the Aztecs, on the Eve of the Spanish Conquest. Translation by Patrick O’Brian. Stanford, Calif.: Stanford University Press, 1961. Soustelle, an authority on Mexican archaeology and sociology, uses the pictographic system and archaeological artifacts of the Aztecs to present the history of this religious warrior society, from daily life to rituals to conflict and conquest. Illustrated.
  • Wood, James B. The King’s Army: Warfare, Soldiers, and Society During the Wars of Religion in France, 1562-76. New York: Cambridge University Press, 1996. Wood brings attention to the military side of the French wars of religion with this analysis of the King’s Army.

European Wars of Religion

Armies of Christendom and the Age of Chivalry

Crusading Armies of the West

Armies of Muḥammad and the Caliphate

The War on Terror

Art and Warfare

Commemoration of War

Film and Warfare

Ideology and War

Literature and Warfare

Music and Warfare

Television and Warfare