Religion and War in the Byzantine Empire

Religion and War in the Byzantine Empire


Byzantine Empire was defined by its Roman heritage, Greek culture and Christian identity. Emperor was head of the state, but was also seen as protector of the faith, which meant that a heresy was automatically rebellion against the Empire. Because the Byzantine Empire was the only real holy Christian empire, Roman Emperor was automatically an emperor of all Christians, any war waged for defense of the Empire was thus also a holy war, supported and sanctioned by God.

Religious Doctrine

Despite the constant warfare, Byzantines never developed the idea of the holy war the way Muslims or Catholics did. War was seen merely as a necessary evil in defense of the Empire and the orthodoxy, and defeats were seen as God’s punishment for sins. But because the Empire was a universalist Christian state defending itself from the forces of darkness, and every attack was attack on the Christian empire, this meant that every war Byzantines fought was automatically sanctified and could be considered holy. Still, when Nikephoros II proposed adopting the Muslim doctrine of heavenly reward for soldiers who died in war, Church rejected this and the idea never took root – murder was still murder.

War was justified if interests and security of the Roman state had been brought into question. When the Empire was under direct threat, even war against other Christians was justified. But the idea of holy war was repulsive to Byzantines, who rejected two fundamental ideas of jihad and Islam: first, that God had ordered forcible destruction or enslavement of unbelievers, and second, that holy war can secure salvation. Byzantines accused Arabs of heresy, because Islam believed that God would sanction destruction of His highest creation and also that all bad things are still God’s will. Constantine VII Porphyrogenetos believed Muhammad had been insane due to latter’s belief that murder can buy heaven. And just like they rejected ideas of jihad, so did Byzantines reject the Latin ideas of deo vult and remissio peccatorum.

While Byzantine authors were not against liberation of Christians from Muslim rule, they disliked the Crusades due to their political, cultural and religious impact. While defensive war (dikaios polemos) was automatically sanctified (as seen with Heraclius), Byzantines did not believe that war could be started solely for religious reasons – whether war was just was not dependant on God’s will, but on nature of the war.

Anna Comnena, the primary source for the First Crusade, defined the war as an armed pilgrimage provoked by Seljuk behavior. She never questions justness of the goal of war – defense of pilgrims and liberation of formerly Christian territores were acceptable. But she never shows understanding for the concept of holy, divinely ordained war. Byzantines also rejected the Western idea of warrior priests. In Byzantine understanding of the just war, it is a sin which God had forgiven due to its justness – but being a forgiven sin, it cannot be used as a way of carrying out penance for other sins. A just war – like Crusades – would remove the mark of sin that war usually carried, but only a just life could secure somebody a place in Heaven. This however also meant than neither God nor religion could justify aggressive warfare: only defense or liberation of Roman lands could be justified. Wars against Bulgaria and against Muslims were both aimed at recovering formerly Roman lands that had been lost to these enemies (Balkans and Syria), rather than acquiring new territory and spreading political dominance of Islam which was the goal of jihad.

The only regularly attested religious aspect of Byzantine campaigns was prayer for divine support offered before the beginning of the campaign. After the Fourth Crusade, Byzantines again repeated accusations of infidelity, but this time aimed against the Crusaders. They also repeated the rejection of Islamic – Crusader idea that God and religion can be justification for war or that going to war can clear one’s sins. This was merely a repeat of long tradition of seeing wars as primarily political.

Only Byzantine war that could be construed as a “holy war” was Heraclius’ campaign against Persia. Heraclius destroyed Persian religious places, and priests followed the army. But while motivation for war was partly religious, there were significant aspects which differentiated Heraclius’ campaign from either Jihad or Crusades. Specifically, there was no sanctification of soldiers for participating in the war, war was not declared by a religious authority, and goal of war was not fundamentally religious.

Byzantine warfare was however significantly sacralized. Timothy Patsisas believes that sacralization of warfare was a mechanism of protecting the soldiers from stress. And a material reward – such as a cow – could be seen as having been provided by God. At latest around AD 460, priests started accompanying the army and leading morning and evening prayers. Church however was against it, as seen from refusal to recognize dead soldiers as martyrs – real martyrs were Christians living under the Muslim rule. In political sphere, religious concerns could start wars, but the goal was always safety of the Empire. The Emperor does not have authority over the Church, but has to work with it.

Campaigns of the Emperor Heraclius

Heraclius is sometimes considered the first Crusader, but historians usually reject such a description. Walter Kaegi believes that Heraclius used religion to motivate his soldiers, but that his wars cannot be considered “holy wars” in the vein of Crusades or the Jihad. George of Psidia praises Heraclius for his just war and describes him as a liberator and a peace bringer, but the goal he identifies is always peace.

Teophanos however identifies Persian attack against the Byzantine Empire as a holy war. Khosrow required the Byzantines to reject Christ and start praying to Sun. Heraclius responded full of “God’s wrath”, and his campaigns are the first time in history that Christian Church financially supported Roman (Byzantine) campaign. Even Church silver was melted down. Heraclius himself outlines the religious motivation for war, though that motivation is closely connected to temporal matters. But the religious nature of war does not prevent it from being a just war, nor does it prevent Heraclius from offering peace to his enemies. Danger of war became basis for the spiritual reward of permanent life.

But even this did not release soldiers of the need for cleansing. Death in battle does not forgive one’s sins, but merely gains worldly salvation for one’s comrades. In response to Heraclius’ utilization of religion, Khosrow took property of churches in Persia, and began to force Orthodox Christians to switch their religion – not to Persian Zoroastrianism, but rather to Nestorian Christianity which was widespread in Persia but persecuted in Byzantium.

During the fifth year of the war, twin miracles happened that saved the Empire – Constantinople was saved from Avar siege, and a hail saved army of Emperor’s brother Theodore. This was interpreted as a clear sign of divine favor. Still, at no point was the goal to utterly destroy the enemy. War ended with a peace agreement that restored status quo, and Heraclius liberated Persian prisoners of war. Victory is celebrated by thanking God and ceremonially returning the True Cross to Jerusalem.

During the war, Persian Emperor (King of Kings) is identified as an enemy of God. But after the war, Roman treatment of Persia was honorable. There was no further reprisals or occupation forces. Yet the Church did identify Heraclius as a Messianic figure. War was jointly declared by the Emperor and the Patriarch. Heraclius’ soldiers were compared to Maccabees, and the war itself completely surpassed all other Roman-Persian wars in both the scale and the consequences of warfare, which does fit with characteristics of religious war. Yet unlike typical religious armies, Heraclius and his soldiers acted with significant restraint and did not cause unnecessary damage. Religious conversion never was the goal and Khosrow’s overthrow immediately opened space for peace talks. In the end, Heraclius’ war fits the criteria of a just war and a holy war both, but former more than the latter.


Byzantine Empire never developed the idea of a holy war. Byzantine wars definitely had religious aspects, and priests participated in them, but this is something that was true from beginning of human civilization all the way to the modern day. Byzantine Church never developed a doctrinal requirement of religious warfare against the unbelievers the way Muslims and later Latin Christians did. While warfare was sacrilized and wars justified in religious terms, sacral elements were always subordinated to secular elements, and the war aims were always temporal. Even Heraclius’ campaign against Persia had a clearly temporal and secular character. Wars were considered just on the basis of natural law, not of divine will, even if two were often conflated. God was a judge, but He could not justify a war if there was no natural and just cause of war. Just war did not incur penalty of sin, but also could not lead to sins be forgiven. Thus, no Byzantine war ever had the nature of religious war so obvious in Jihad and the Crusades.


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