The way the story is told today the Crusades was all about the evil Christians jumping on the peaceful Muslims, a brutal and unprovoked attacks against a sophisticated and tolerant Muslim world, who were minding their own business in their own lands.
Well here is how it actually happened, shortly after Mohammed’s death the Muslim took over the lands of Palestine, Syria, and Egypt, and converted all the Muslim to Islam, made them slaves, or killed them. By the eighth century, Muslim armies had conquered all of Christian lands in North Africa and Spain. In the eleventh century, the Seljuk Turks conquered Asia Minor (modern Turkey), which had been Christian since the time of St. Paul. The Eastern Roman Empire first ruled by Constantine and had converted when he saw a Cross in the sky before the Battle at Milvian Bridge on October of 312 AD, now known as the Byzantine Empire, was reduced to little more than Greece. In desperation, it was the emperor in Constantinople who sent word to the Christians of western Europe asking them to aid their brothers and sisters in the East.
That is what gave birth to the Crusades. They were not the brainchild of an ambitious pope or rapacious knights, but a response to more than four centuries of conquests in which Muslims had already captured two-thirds of the old Christian world. At some point, Christianity as a faith and a culture had to defend itself or be subsumed by Islam. The Crusades was that act of defense. At the Council of Clermont in 1095, the response was tremendous. Many thousands of Knight and men-at-arms took the vow of the cross and prepared for war, Kings pledge their life and wealth to Why did they do it?
There are four main reasons why people in the medieval ages went on the crusades: Some went because they wanted to take back Jerusalem for they reasoned that it was rightfully Christian since it is there where Jesus died. Some did it for honor, revenge or love. And there were those who wanted their sins to be forgiven, to go to heaven or to take back goods from the Holy Lands, or because they had committed a crime and were forced by the church to go on a Crusade. And some people, just in our military today, just went on for fun. So the answer to the why question has been badly misunderstood, and severely misstated.
In the wake of the Enlightenment, it was usually asserted that Crusaders were merely lack lands and ne’er-do-wells who took advantage of an opportunity to rob and pillage in a faraway land. The reasons they said they were doing it for was only a front for darker designs. Knights, however, were generally wealthy men with plenty of their own land in Europe history has shown, and even the wealthiest could easily impoverish themselves and their families by joining a Crusade.
Some Christians also went on Crusades because they wanted to go to heaven or wanted to shorten their time in Purgatory. There were those who went to be forgiven their sins. Some people went because they knew that if they killed a Muslim they would be allowed to take all he had, but the truth was that the Crusades were notoriously bad for plunder while a few got rich the vast majority of them returned home with nothing. Some were forced to go on crusades by the church because they had committed a crime. This from an English trial in 1291 which said, “You have been found guilty of hitting a priest with your sword. For this outrage you must join a crusade or pay a suitable soldier to go instead.”
None of the Crusader went to force Muslims to become Christians, no Crusader ever forced a Muslim to become a Christian! In fact the Muslims who lived in Crusader-won territories through out these wars were allowed to retain their property and livelihood, and always their religion, and throughout the history of the Crusader in the Kingdom of Jerusalem, Muslim inhabitants far outnumbered the Catholics. It is true that in the 13th century the Franciscans began trying conversion efforts among Muslims, but these were mostly unsuccessful and finally abandoned. These efforts were by peaceful persuasion, not by the threat of violence or the force of taxation.
For centuries, Christian pilgrims traveled from Europe to Jerusalem. In the 11th century, however, the Seljuk Turks, who were Muslim, began to interfere with these pilgrimages. In 1071, the Seljuk Turks fought against the Byzantine Empire at the Battle of Manzikert. The Byzantines, who were Christian, lost. The Byzantine emperor asked the Christians in Europe to help protect his empire from the Turks. In 1095, Pope Urban II called for a crusade against the Muslims to regain control of Jerusalem.
Pope Urban II called for a crusade against the Muslims to regain control of Jerusalem. To all crusaders, he gave this promise:
“All who die by the way, whether by land or by sea, or in battle against the [Muslims], shall have immediate[forgiveness] of sins.”
-Pope Urban II, 1095
Latter Pope Innocent III, l wrote:
How does a man love according to divine precept his neighbor as himself when, knowing that his Christian brothers in faith and in name are held by the perfidious Muslims in strict confinement and weighed down by the yoke of heaviest servitude, he does not devote himself to the task of freeing them? …Is it by chance that you do not know that many thousands of Christians are bound in slavery and imprisoned by the Muslims, tortured with innumerable torments?
The Crusade by the Christians of the time was seen as an errand of mercy to right a terrible wrong. As Pope Innocent III wrote to the Knights Templar, “You carry out in deeds the words of the Gospel, no Greater love than this hath no man, that he lay down his life for his friends.'”
I am not saying that some Christians did not do some terrible things in the two hundred years of the Crusades, for indeed some of the Crusaders killed not only Muslims, but Jews and other Christians as well. In April 1204, the Crusaders of Western Europe invaded and sacked the Christian city of Constantinople, what I am saying is that they had just cause to go and defend Christendom.
By the way, Crusade is a modern word not coined until 1706, respelling of croisade (1570s), from Middle French croisade (16c.), Spanish cruzada, both from Medieval Latin cruciata, past participle of cruciare “to mark with a cross,” from Latin crux (genitive crucis) “cross.” Other Middle English forms were croiserie,creiserie. Figurative sense of “campaign against a public evil” is from 1786. The ones who fought in what we call the Crusades called themselves Pilgrims.