How was crusading justified?
Christ leading crusaders into battle, detail from an Apocalypse, with commentary (The "Queen Mary
Apocalypse"), early 14th century, f. 37 (British Library)
Just warfare
Crusades were wars—that is firm ground. More specifically, crusading was represented as
just warfare, according to the idea of just war established by St. Augustine of Hippo.
Augustine wrote that warfare was sometimes a necessary and lesser evil in certain
conditions. Specifically, a war could be just if there was:
a) just cause,
b) legitimate authority, and
c) right intention.
A just cause was a previous injury or act of aggression. As a result, crusading was described as
defensive.
A legitimate authority was just that: an authority who held the power—granted by God, from Augustine’s
perspective—to invoke war. Crusading, it was argued, was authorized by popes and legitimate secular leaders.
Participants had the right intention if they believed war was completely unavoidable and sought only to use minimal
force to check aggression against them. In theological terms, participants were supposed to be motivated by Christian
love, (i.e. charity), rather than by anger, hatred, or fear. Crusade supporters stressed that participants were driven by
the desire to help liberate purportedly oppressed Christians and save them from purported atrocities and slavery, and
the desire to do the same for the personified Church or even Christ himself, both supposedly injured by the enemies of
the crusaders.
But participating in a just war could still be sinful. For example, Duke William I of Normandy’s invasion of
England was considered just, but Norman participants had to do penance afterwards. So saying that
crusading was a just war wasn’t enough. Many writers communicated that crusading was holy warfare,
meaning that it was a just war that was not only authorized but also realized by God himself. In theological
terms, then, God was the one taking action; God was the one waging war. Crusaders were divine tools,
rather than moral agents in their own right. It was this belief that led one monk, Guibert of Nogent, to title
his account of the First Crusade “The Deeds of God done through the Franks” (he was not-so-subtly
revising an earlier, and in his opinion theologically crude account, titled “The Deeds of the Franks”). Of
course, if a crusade was a holy war, then the enemies of crusading were enemies of God and the whole
Christian faith, not just enemies of particular Christians—and that was precisely how Muslims and other
crusader targets were depicted in many pro-crusade accounts.
Penitential warfare
Finally, crusading was also represented as penitential warfare. This means that crusading was believed to
be an act of penance—a way to make amends to God for sins one had committed, so that an individual
could achieve salvation. It means that crusading was not simply seen as a necessary evil—it was seen as
a positive spiritual good for those who participated. Participants were not merely excused for their
involvement; they actively acquired spiritual merit. In the simplest terms, crusading was presented as a
good deed, even though it involved killing people.
To make sense of this, we need to recognize that violence was often perceived to be much more morally
neutral in medieval Europe than it is today. Violence acquired its moral value from intentions and context,
like who was performing the violence and to whom it was done (this should remind you of Augustine’s just
war theory: cause, authority, and intentions). Thus, the same action—let’s say, hitting someone in the
face—could be immoral and unchristian in one context, and moral and Christian in another.
Given the penitential element in crusading and the number of expeditions that involved long journeys to
holy places, it is not surprising that crusading was often described as a pilgrimage, a journey to a holy
location like a shrine, a church, or even an entire city, like Jerusalem. Those who went on pilgrimage
frequently sought spiritual advantages, like forgiveness of sins or a closer relationship with God or a saint;
they also sometimes hoped for more earthly advantages, like healing. Pilgrimage was a sacred act for
medieval Christians, and was itself often an act of penance (sometimes voluntary, sometimes assigned by
a priest in confession). Crusading borrowed some of the language, rituals, and symbols of pilgrimage, and
shared its penitential nature.
Changing definitions
It’s important to emphasize again that people didn’t write a theory of crusading in advance. There wasn’t
even a specific word for “crusade” until more than 100 years after the First Crusade. In addition, the nature
of crusading seems to have operated differently and meant different things depending on time, place, and
participants.
Text by Dr. Susanna Throop