The Crusades were a development of the High Middle Ages that connected Europe with Islamic civilization, and began weakening European feudalism throughout the twelfth and thirteenth centuries. The first of these Crusades were initiated by the papacy, as well as popular religious beliefs, and later had consequences for Europe. One of the results of this unified effort that channeled military force into a common effort was responding to the higher authority of the papacy for the sake of piety that was characteristic of the spirit of the times, and another was potentially slowing the advance of Islam encroaching into Europe, after territories that were occupied by the Crusaders had been lost, along with the cost of a great deal of human lives while both sides fought for their respective religious beliefs over the possession of disputed territory.

The initial cause for the European Crusades was that Jerusalem and the region of Palestine fell from Christian hands to Arab invaders in 637, and the Islamic Seljuk Turks who took control of the city and region in 1065 closed the city to the religious traditions of Christianity. The Turkish sultan then looked to invade Constantinople, and in the face of this threat, Emperor Alexius Comnenus then turned to the papacy for help in 1095 to defend against their aggression. Pope Urban II saw Alexius’ request for help as an opportunity to make the Papacy the undisputed leader of Christendom by liberating the eastern Christians and Jerusalem from Muslim domination. Urban was much more interested in who ruled Jerusalem, as taking this city would bring blessings on all of Christendom, along with enormous prestige for the papacy. He thus called for a crusade, or holy war, against Islam, promising penance for the crusaders and be assured of salvation in a war of liberation that would also be a pilgrimage with a penance that was so severe that it would provide remission for all previous sins.

This would also channel their energy away from private warfare, and toward the assistance of fellow Christians. Different armies of crusading knights and peasants then travelled to the Holy Land as a result of being devout, while under the burden of guilt of sinfulness under the auspices of the authority of the Papacy that had sanctioned warfare against Islam. By the end of the Third Crusade in 1192, a truce was reached between the Crusaders and Muslims, by which Christians were assured free access to Jerusalem, but nothing more was gained. Jerusalem was later permanently lost in 1244.

The first reading sample indicates how launching warfare at the behest of the Papacy appeared to the Crusaders as a justifiable conflict for the sake of defending Christianity. However, any earlier military expansion was inexorably lost, as is indicated in the second reading, when the Crusaders were repelled in Islamic counter-attacks while Muslims were forced onto a defensive stance, in reaction to first Islamic territorial expansion into what the Papacy had declared to be Christian holy land. The second reading also adds how the Crusades had political consequences. There was the aggravating underlying factor of the Crusaders having been implicated in the internal affairs of the Byzantine Empire during this time. This led to the lasting enmity of the Byzantine Empire against the Papacy as the titular head of the western European states that conclusively sealed the division between the Catholic West and the Orthodox East, and also the eventual expiry of the Byzantine Empire that would not again request defense against the same external threat. An additional long term consequence was the establishment of Crusader states that Muslims took over, and became new geographical entities in the Middle East for nearly two hundred years. The first reading sheds light on the spiritual motivation the Crusades under Papal authority, while the second reading provides considerations for their consequences, including the creation of territorial changes at the cost of a great deal of loss of life for the sake of fighting for an overriding ideology. These series of ongoing conflicts that had forced Islamic forces into a defensive stance also precluded the unity of Islam into a unitary state. This effect in turn prevented further Islamic expansionist aggression into Europe, while the Crusaders themselves considered themselves to be ideologically justified in protecting Christendom against this Islamic encroachment.

The separate contents of these two readings demonstrate the underlying ideological cause for the Crusades, and although the Crusaders failed to achieve the primary goal of recovering the Holy Land, there were long term political consequences for European history. In comparison with the First World War in view of causes and consequences for that conflict, most leaders in most countries and much of public opinion everywhere in Europe likewise did not consider war to be something evil, as was indicated in the first reading, particularly if it meant continuing politics by other means. The end of this conflict likewise resulted in territorial changes in the form of establishing new states, as was indicated in the second reading. A more significant consequence was hindering further military aggression for a certain amount of time. The second lesson draws attention to these lessons from the past that were repeated in the future.