What was the philosophy of the crusaders?

[Condottiere 40K]

Too big not to fail.

[Cyclops]

There's a lot of strands. Alexios Komnenos called for Christians to support the Christian Empire: in the ERE political thought identified all Christians as subjects of the Emperor. This is shown by treaties between the Caliphate and ERE where Christians in Jerusalem are called the Emperor's subjects, and Muslims in the ERE are the Sultan's subjects.

Politically he was risking a lot to call on schismatic westerners to come to his aid as there was some barbaros claiming the title of western Augustus, and the Patriarch of Rome had been behaving like a politically independent monarch for some time, but according the Konstantinopolitan political theory he was a legitimate ruler calling fractious subjects to put aside their petty claims and come to their legitimate monarch's call. Thewar was not holy, war was considered ecvil, but serving the Emperor was the duty of every Christian to his way of thinking.

The Papacy transformed the message. Deus lo vault does sound a lot like the call to holy war. This raises the vexed question of the Christian attitude to war and how it varied across time and space. Essentially the Roman legal concept of Just War had melded with a Christian notion "killing is bad" to form the ERE attitude that all wars were necessary sins to be atoned for, and typically any war beyond the Empire's former boundaries was morally questionable. War might support the Emperor's right to rule (justified by religion) but war itself was in no way holy.

In the West the influx of bloodthirsty military elites who gained status and resources by armed conflict put the Papacy and its loyal bishops in a difficult position. In the absence of a religiously credible secular overlord the Papacy "allowed' certain kinds of war, mostly bleating about pillaged churches and begging robber barons to cease plundering Christians. So there was a vague notion of the Pope being able to "allow" certain wars.

The third factor must surely be the concept of Jihad. The concept of "crusade" as a religiously motivated war that conferred grace by participation in killing was new to Christians...sort of. In Iberia the Reconquista had (even before the crusades) religious orders of knightly warriors dedicated to attacking Islam. These knightly orders probably inspired the Templars, Hospitalers, and Teutonic knights, and they may have contributed the idea of sacred warfare.

The common element in the crusades and Reconquista is the rollback of Islam. Christians however warlike answering the prophet's call to Jihad had no religious answer, until the call to Crusade gave a unifying vision to Frankish military aristocrats who until that time had been almost impossible to unite.

The philosophically simple Franks embraced the idea of killing for God and making a moral (and sometimes temporal) profit. Many crusaders may have gone for plunder or to pinch a fief, but at least as many sacrificed wealth or life for no gain.

The Papacy did try to provide leadership but sadly the very able papal legate Adhemar de le Puy attached to the crusading forces died before he could impose a uniform political or philosophical framework on the forces.

There are some clues to the Papacy's philosophical approach to the crusades: the legate imposed a political uniformity on the crusaders (which almost disintegrated on his death) insisting fealty was sworn to the Emperor (so its clear the Popes did not seek at that time to overthrown the ERE). The Siege of Antioch was punctuated with religious rituals far beyond the normal masses and blessings and an atmosphere of miracles and visions was fostered. Its clear the Papacy saw the crusades as a war made holy by its objectives, a clear contradiction to the ERE position, and one well calculated to motivated the less cultured Frankish warriors to rare conformity.

It is surprisingly like the concept of Jihad, albeit less developed. Participation or death in the holy struggle brought grace. Unsophisticated warriors were motivated to great deeds.

Its hard not to see the concept of Crusade as a in imprint of the Islamic concept of Jihad on Papal and to an extent Frankish philosophy, albeit a short lived one. Christian religious thought is not well adapted to genuinely supporting war and the concept of crusade quickly broke down into more cynical exercises: the sack of Konstatinopolous in 1204 is the death knell of Crusades as a genuine movement.

However the first crusade demonstrates the power of the concept of Holy War.

[Condottiere 40K]

A defensive war is just, and Jerusalem was considered Christendom's most sacred city, and had to be recovered to safeguard the pilgrimage there.

Since the Catholic Church for all intents and purposes excommunicated the Orthodox one, it's doubtful any lingering authority from either a religious or secular source from Constantinople would be recognized in the west.

[Colossus]

When i am talking about crusaders i do not talk about the leaders of the crusades. I am talking about the religious military orders like knight Hospitalier. They must have had a code of ethics i assume

The Military Orders were not crusaders.

I consider crusaders to be a catholic version of jihadists

While there are some general similarities, such as spiritual reward (which is to be expected, given that there are between the two religions themselves), there are fundamental differences between the two - it would be incorrect to see them as variations of the same thing.

The main difference is that jihad is a central component of Islam as described in the Qur'an and other teachings. It is both spritual and physical, collective and individual, and is expected of anyone who is capable.

'Crusade' is obviously not a fundamental component of Christianity, and the precise term is partly historiographical (until a certain point, was referred to only as pilgrimage with pilgrims, before crucesignatus became a phrase for those signed with the cross). Rules over where violence is justified are even more vague and often contradictory. 'Just war' began to be formulated in the 4th/5th century with Augustine of Hippo. The circumstances around the crusades evolved in the 11th century with the meaningful increase in papal power, and the willingness of the pope to grant spiritual rewards for those who undertook particular action. The definition of a crusade is by no means agreed on, but includes things such as taking a vow, papal authority, wearing of a cross and granting of indulgences and privileges. This things were framed around specific goals, and the participants took vows in relation to such goals. Therefore, 'crusade' was not a fundamental component of Christianity, but a fusion of concepts surrounding pilgrimage and just war, the latter of which itself evolved over centuries. This was not a universal obligation or a continuous state of being, but a call in response to a specific event or situation involving a defined set of individuals.

[Ludicus]

Just a little nitpick, that quote is from Raymond of Aguilers, .

The version of Raymond of Aguilers is slightly different. Page 260, Chapter 7,Siege and capture of Jerusalem,
The First Crusade: "The Chronicle of Fulcher of Chartres ...