The Crusades were a very far-reaching historical event in Western history, lasting nearly 200 years from the beginning of the First Crusades in 1096 AD to the fall of the last Crusader state in 1291. In order to compete with Islam for the Middle East, the Western countries launched a total of 9 crusades, most of which ended in failure, protracted wars brought war to the Middle East, but also promoted cultural exchanges between Europe and the Islamic world, Europe was once a powerful church force, with the defeat of the crusades also declined, and finally replaced by the feudal lords of European countries.
When it comes to the causes of this war, there are four main aspects:
The first was that the Islamic forces of the time had seriously threatened Europe.
Since the first half of the 7th century AD, Islamic forces have gradually emerged in the Arabian Peninsula, and since then they have embarked on a path of rapid expansion. The Eastern Roman Empire, with Christianity as its state religion, lost vast areas of Syria, Palestine, Egypt, and North Africa under the blows of Islamic forces, and by the end of the 11th century, Muslim armies had occupied almost all of Asia Minor, with their armies advancing on Constantinople, the capital of the Eastern Roman Empire.
After the Islamic forces conquered North Africa, their forces soon crossed the Strait of Gibraltar and invaded Spain, which once occupied all of Spain. At that time, the Islamic forces were in full swing, and even once had to cross the Pyrenees and attack the territory of France, and the expansion of Islamic forces had seriously threatened Europe and the Christian forces in Europe, and the expansion of The Resistance to the Islamist forces had become an urgent thing for European Christianity and for the lords of European countries.
The second was that the power of the Christian church began to decline, and in order to increase the power of the church, Pope Urban II launched a crusade
Since the Middle Ages, Europe has basically been in a state of feudal lordship. At that time, the church and the feudal lords were both a contradiction and a community: the church had no army, and the power of the church could only rely on the kings and feudal lords of various countries; on the other hand, the Europeans at that time generally believed in Christianity, and the Holy See could influence the kings and feudal lords of various countries through the monopoly of the Christian faith, that is, the monopoly of ideology, the most famous of which was the "Cassano Incident".
▲ The humiliation of Cassano
In 1077, The Holy Roman Emperor Henry IV refused to obey the intervention of the Holy See in his personnel appointments, leading Pope Gregor VII to excommunicated him. Extermination meant that all Christians could not have any contact with Henry IV and had to renounce their friendship with him. After Henry IV was excommunicated by the Holy See, he soon became a loner, and in the face of the holy see's excommunication, Henry IV finally resigned, wearing coarse cloth clothes and bare feet, standing in the snow in front of The Cassano Castle where Gregor VII was located, for three days and three nights, before receiving the "forgiveness" of Gregor VII and being exempted from excommunication.
This was naturally a great shame for Henry IV, and in the days that followed, Henry IV, while pretending to be a grandson in front of Gregor VII, constantly purged Gregor VII's power, and finally Gregor VII left the Vatican under the military threat of Henry IV and died in his hometown.
Pope Urban II, the initiator of the Crusades
After Gregor VII to the time of Urban II, the Holy See changed its tough attitude towards feudal lords and turned to increasing the influence of the Holy See through political means, and the most important to enhance the influence of the Holy See was the common enemy of the Church and the lords, the Islamic forces, so Urban II proposed that the lords of Europe participate in the crusade of the Crusades.
For the Holy See, the use of the military power of the European lords to launch the Crusades can first open up new spheres of influence for Christianity, and second, it can also incorporate the armies involved in the crusades into the management system of the Holy See and enhance the control of the Holy See over the army. Of course, launching the Crusades was an important reason for the feudal lords of European countries to add new territories to them, and it was also an important reason for their participation in the Crusades.
The third is out of faith in Christianity
You might argue that this reason is too far-fetched, that the Europeans launched the Crusades in essence for profit, but in terms of the actual situation at the time, there were indeed many people who participated in the Crusades for the Christian faith. For example, during the First Crusade, a French hermit named Pierre persuaded about 100,000 civilians to form a "civilian crusade", and a considerable part of this "army" participated in the crusades under the influence of fanatical religion.
For example, during each Crusade, whether they were kings, lords, knights, soldiers, and priests who participated in the crusades, many of them also participated in the crusades out of faith in Christianity, believing that they were born with the mission of protecting Christianity.
Even during the Crusades, many Islamic Turks converted to Christian armies, and these Turks, generally known as "Turks," willingly fought for Christianity after conversion at the expense of their lives.
Of course, among these people, the most famous are the three major orders: the Knights Hospitaller, the Knights Templar and the Teutonic Knights, most of whom participated in the Order, gave up their original territory, donated all their property to the church, and lived a poor war life in the Middle East for a long time, and were the most determined people of the Christian faith.
PS: The people who can join the three major knights are all people with knighthood, these people have more or less some territories in Europe, and they all belong to the local local tycoons today.
Out of faith in Christianity, it really inspired a lot of people at the time.
The fourth is for profit
The pattern after the end of the First Crusade
For the Holy See, the Crusades were launched to increase the power of the Holy See. For feudal lords, interest was also a reason for them to wage war. For example, after the end of the First Crusade, the families of Godefroy, Duke of Lorraine, became kings of the Kingdom of Jerusalem, Saint Gil, Count of Toulouse, established the Fides of Tripoli, Poemundo established the Principality of Antioch, and even Baldwin, who was not a lord before the Crusades, established the Countate of Edessa.
In addition, during the Crusades, Christians established a large number of commercial cities along the Mediterranean coast of the Middle East, which promoted trade between the Middle East and Europe, especially some city-states such as Venice, Florence and Pisa, which also made a windfall in these trades.