According to historians, the Crusades were a series of military attacks launched by Western Europe on Muslims and the Islamic world from 1095 to 1291. These wars which were sanctioned by Christian leadership and Catholic Church[1], took place between the followers of two big and powerful religions in a very vast geographical area. Christians maintain that religion was the main causes of the campaigns but Muslims reject this allegation saying that religion was simply a pretext for gaining more power, conquering more lands and expanding hegemony of religious authorities and Western governments.
The campaigns sponsored by the papacy against Muslims are technically called "crusades". This is a new term that was not used in the middle ages[2]. It was only in the 18^th century that the term began to be widely used.[3] To show that the wars were launched with a purely religious objective, Christian historians used a number of terms and expression such as the "Hajj (pilgrimage) journey", "sacred journey", "the journey to Quds" "Jesus Christ's plan" and thousands of other words with religious implications and meanings. That was why those who took part in these battles were used to be called for many years as "Hajjaj" (pilgrim). [4]
On the contrary, Muslim historians made use of words such "Foreigners" which implied they were strangers or outsiders who did not belong to the Muslim land or ethnicity[5] and who used religion simply as a pretext for gathering more power, conquering more lands and expanding hegemony of the religious authorities, a struggle that existed between Eastern and Western sides of the globe even before Islam.
The term "crusade" was used because of the apparent use of "cross" in the wars against Muslim; because the cross which is an upright post with a transverse bar, used in antiquity for crucifixion, is a Christian symbol and regarded very sacred. That was why it was always used by Christian preachers, missioners and fighters as a symbol of Christianity. This religious symbol was visibly used by crusaders in their expedition and campaign against Muslims.
Crusades as a great social-political-religious phenomenon which last for decades, and involved millions of people had a lot of positive and negative effects. There were different factors involved in this historic event which we are going to explore as we discuss the subject-matter further. We shall now briefly review the causes of the crusades as follows:
Causes of the Crusades
In the early Christian centuries, the world of Christianity was divided into two parts each belonging to a sect of Christianity. The east belonged to the orthodox Christianity and the west to catholic Christianity.
In the wake of battles against Muslim and non-Muslim tribes, the emperor of Christianity of the East with Constantinople being its capital had grown very weak and debilitated as it had no sufficient military force to defend itself.   In opposition to the Christian empire, the Sunni dominated government which was in the hand of the Seljuks[6]and was ruled by Malek Shah was considered to be a serious threat to Constantinople and Christianity of Eastern Europe.
As well, in a famous battle known as the battle of Malazgerd that occurred between the two groups, the Seljuks were able to defeat the Byzantine Empire. The result of this battle which took place in the center of Armenia, was that three fourth of Minor Asia fell to the Saljukid Turks. [7]
In the wake of these events, Constantinople was seriously threatened by the Saljuks. Then the Byzantine emperor appealed Pope for help to confront the Saljuks. The Byzantine emperor's appeal to his opponent i.e. Pope for help was definitely very hard, because there was a long-standing animosity between the two groups.  The threat of the Constantinople was considered to be a very serious danger for Christians and it was one of the causes leading Christians to make a public call for the first crusade attack or war against Muslims.[8]
On the other hand, the news had spread that Muslims who were going to Bait al-Maqdis along with Christian pilgrims did not behave well with the latter; they acted outrageously and desecrated Christian sacred symbols. The news circulated that Muslims had confiscated some of the monasteries.[9] That was why the Christians of Bait al-Maqdis informed Pope Urban II who proclaimed the First Crusade with the stated goal of restoring Christian access to holy places in and near Jerusalem.[10] These were some external causes which gave an excuse in the hand of Pope and the West to launch an attack on Muslims.
In addition to these external causes, there were internal factors in the Christian society as well which caused the war to be inflamed. In the eleventh century, drought and starvation had entailed misery and poverty of the European community. They lived poor and superstitious lives. Destruction and frustration were so rampant in the cities that Christians were made to look for a way out, a solution to remedy the situation.  Christian sermonizers descried the East as full of prosperity and blessings telling people that if they marched towards the East they would get worldly benefits and blessings. This motivated many people to take part in the battles.[11]
In addition, the Church Lords and great European kings coveted the Islamic lands which were definitely full of blessings and fortunes for them. They thought they could take more lands to expand their territory and rule.
Start of Crusades
Pope Urban II proclaimed the crusades. Of course, he had proclaimed the crusades before Pope Gregory VII.[12] During his time, the Saljuks were very powerful and united and Pope could not launch a Christian war. As a result, he could not start a war but Pope Urban II who was very loyal to Gregory VII (the pope before him) proclaimed the crusade provoking the Christian world against Muslims. He held a massive gathering with prominent people from various segments such as government authorities, the feudal, knights and Church officials attending it. This gathering was held in 1095 in Clermont of France. The gathering was known as Council of Clermont.[13]
Pope Urban II delivered a very important speech at Clermont which can be termed as the start of the crusades. In this furious speech, he spoke against Muslims and enumerated Muslims' actions against the Christians of the East so as to make Western Christians to react.[14] More importantly, he enlivened their aspiration regarding the Holy Land (Bait al-Maqdis). He stated to them that Bait al-Maqdis had fallen to Muslims and they were ruling the city. Given the great importance of the city of Bait al-Maqdis to Christians, this speech created a wave of hatred against Muslims.
Christians who considered this war to be a holy war and believed there was much good in it for them, joined the war.  Christian bishops went from one city to another and one village to another propagating for Christian army and causing a lot of people, especially the indigent and the poor to join the army.[15] In addition, the material gains which this war could entail created incentives for many people and caused many of the feudal and important figures of the time to join the army.
On the contrary Muslim countries were disunited and were also suffering from setbacks as internal wars were going on among Muslims.
Finally, the crusades started and Christians entered a war against Muslims which took about two hundred years to come to an end. Historians have divided these wars into as many as eight periods or phases the most important and most effective of which was the first crusade attack which resulted in the occupation of Bait al-Maqdis (Jerusalem)[16]. This holy land remained under the occupation of the crusaders for 83 years until Salah al-Din Ayyubi, better known in the West as Saladin (532 – 599 A.H.), prepared an army of strong and dedicated Muslim soldiers and restored the land.[17] This was not the end of the war because the crusaders imposed a series of wars on the Islamic world until the year 1291 but they never succeeded in taking back the Holy Land from Muslims. Indeed many believe there was only an interval in 1291 in the wars between Muslims and Christians and the wars never ended. It has been going on as of today. The wars imposed by the Christian dominated countries on Bosnia and Herzegovina, Lebanon, Palestine, Iraq and Afghanistan are aimed at realizing the goals of the crusaders to destroy Muslims and loot their properties.
Consequences of Crusades
The crusades which lasted about two hundred years definitely entailed a lot of devastations and destructions which were the worst of the results for both sides. The negative and destructive impacts were imaginable for every individual. On the contrary, however, the positive consequences of the crusades which shaped the future of particularly Europe were of paramount importance and need to be explained further. We shall now briefly enumerate the negative impacts of these wars for Christians:
1. Correcting the European people's mentality about Islam and Muslims as well as knowing the great Islamic civilization and its humane doctrines.
2. Formal opposition of the Catholic Church on the part of Christians and calling for reform in the Christian religion in which the Catholic Church had no power.
One of the most important impacts of these wars on Christians' lives was the fact they lost their confidence in Pope and the Catholic Church. People were tired of the wars and campaigns which had been launched by Catholic Church. As a result, anti-religious nucleuses came into being in Europe and even those who were interested in Christianity but had become aware of Church problems began to seek reform in Christianity. Although the reforms took place centuries later by people such as Luther and the likes, the foundation for reform was laid as a result of the Christians observing Islamic civilization and being influenced by it.
3. Formation of the Western civilization: There is no denying that the crusades have been one of the main causes of the formation of the Western civilization as they helped acquaint Europeans with Islamic civilization finally laying the foundation of modern civilization. These preparations can be followed up in two parts:
a) Scientific prosperity: The clear and tangible influence of Islamic civilization and culture on Western human sciences cannot be denied. The translation of various Islamic sciences particularly and most importantly the medical science into Western and European languages, and establishment of universities as a consequence of the Europeans becoming familiar with Islamic civilization are examples of the post-war developments. The spread and progression of medical sciences, establishment of hospitals in Europe and amazing developments in medicine were achieved after Muslim doctors' experiences and works were transferred and made available in Europe. Books authored by Muslim scholars in medicine found their way through Spain to Europe especially after the crusades. Those books were taught for decades and centuries in European universities. One of the most famous of those books was "The Canon" by Avicenna which was taught for centuries in European universities.[18]
Medieval thinkers getting familiar with Muslim scholars' thoughts, took philosophy and monotheism which were two interrelated subjects to Europe whereupon these thoughts heralded the end of dark ages and the start of a new era characterized by scientific progress and prosperity. The advent of reformist movements, anti-superstition campaigns and intellectualism reaching their peak two or three centuries after the crusades were not disconnected with rationalism of the Islamic philosophy. Averroes (Ibn Rushd) who lived in the sixth century of the Islamic calendar was one of those influential Muslim scholars. Christian teachers, students and intellectuals of Europe were influenced by Averroes' thoughts. His philosophy dominated intellectual schools from late thirteenth century to the end of the fourteenth century. Averroes subscribed to reason and rationality and maintained that everything had to be subservient to reason. His books used to be taught in a Paris university after some modifications were made and points objectionable to bishops were removed.[19]
b) Social consequences: The wars had a lot of social consequences in the lives of the Europeans. They included the spread of music, becoming familiar with variety of foods, clothes, make-ups, house decoration and some oriental norms and customs.[20]
Back then the Europeans were uncivilized. Apart from the capital of Western Rome, the rest of the residential centers of Europe, were devoid of big cities, civilization and scientific centers and were run as feudal units. In the wake of these social changes, feudal thinking was replaced with Bourgeois thinking; feudal thought is the ownership towards the property, subjects and products. In this kind of ownership, the farmers were dependent on land and were bought and sold along with the land. But the Bourgeois thinking is opposed to feudal thinking. In Bourgeoisie, people should live a city life and capital is used to boost market and separate industries. This war caused the feudal government to change into Bourgeoisie.[21]
The industry and technology of the West, especially in the crusades, began to copy and derive from eastern models. The impacts of these derivations and imitations in weaponry, clothing and housing were vividly visible especially in the twelfth and thirteenth centuries. As the living conditions improved quantitatively and qualitatively, industry and trades also made headway. Woodworking industry, goldsmith, tiling and glass-making are industries that Europeans borrowed from Muslims and became common in Europe over time.  The people of the city of Venice learned glassmaking from the people of Ṣōr (Tyre).[22]
When it comes to skills and technical matters, the East had a very profound influence on Europe. The Crusaders seeing different types of fine industries spread from Constantinople to Egypt, began to learn how to make fine things and change their tastes.  The art of architecture changed thoroughly in Europe. The European classical architectural style had three main features. 1 – Thick walls 2- Low roofs 3- Lack of light. Seeing the mosques and sultans' palaces, they began to adopt Islamic architectural style which had certain features e.g. 1 – thin walls 2- high roofs 3- use of light 4- decorations and color glasses.[23]

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