The Crusading movement of the High Middle Ages began as a theological concept. Pope Gregory VII, like many of the popes during the last half of the eleventh century, received appeals from the Byzantine emperors in Constantinople for Western aid against Turkish incursions. It was not difficult for Gregory, nor the clergy that followed him, to come to an understanding that war against the Seljuk Turks could be not only justified but understood as an obligation under the tenets of the Christian faith, for the Church was already in the habit of blessing Christian warriors in their struggles against pagan forces. But the appeal to defend Jerusalem carried far more powerful spiritual connotations, since this was the Holy City where Christ had walked the earth. The idea of the Crusade as not only a just war executed in self-defense, but also as a pious protection of the physical site of Christ’s mission in the world came to define the theology of religious warfare throughout the Crusading era. The Crusader, then, took on a profound spiritual role in the medieval imagination; he was a fighting pilgrim, whose combative functions were accompanied by a pious reverence for the Holy Land.
"You have seen for a long time the great disorder in the world caused by these crimes. It is so bad in some of your provinces, I am told, and you are so weak in the administration of justice, that one can hardly go along the road by day or night without being attacked by robbers; and whether at home or abroad one is in danger of being despoiled either by force or fraud. Therefore it is necessary to reenact the truce, as it is commonly called, which was proclaimed a long time ago by our holy fathers. I exhort and demand that you, each, try hard to have the truce kept in your diocese. And if anyone shall be led by his cupidity or arrogance to break this truce, by the authority of God and with the sanction of this council he shall be anathematized."
After these and various other matters had been attended to, all who were present, clergy and people, gave thanks to God and agreed to the pope's proposition. They all faithfully promised to keep the decrees. Then the pope said that in another part of the world Christianity was suffering from a state of affairs that was worse than the one just mentioned. He continued:
"Although, O sons of God, you have promised more firmly than ever to keep the peace among yourselves and to preserve the rights of the church, there remains still an important work for you to do. Freshly quickened by the divine correction, you must apply the strength of your righteousness to another matter which concerns you as well as God. For your brethren who live in the east are in urgent need of your help, and you must hasten to give them the aid which has often been promised them. For, as the most of you have heard, the Turks and Arabs have attacked them and have conquered the territory of Romania [the Greek empire] as far west as the shore of the Mediterranean and the Hellespont, which is called the Arm of St. George. They have occupied more and more of the lands of those Christians, and have overcome them in seven battles. They have killed and captured many, and have destroyed the churches and devastated the empire. If you permit them to continue thus for awhile with impurity, the faithful of God will be much more widely attacked by them. On this account I, or rather the Lord, beseech you as Christ's heralds to publish this everywhere and to persuade all people of whatever rank, foot-soldiers and knights, poor and rich, to carry aid promptly to those Christians and to destroy that vile race from the lands of our friends. I say this to those who are present, it meant also for those who are absent. Moreover, Christ commands it.
"All who die by the way, whether by land or by sea, or in battle against the pagans, shall have immediate remission of sins. This I grant them through the power of God with which I am invested. O what a disgrace if such a despised and base race, which worships demons, should conquer a people which has the faith of omnipotent God and is made glorious with the name of Christ! With what reproaches will the Lord overwhelm us if you do not aid those who, with us, profess the Christian religion! Let those who have been accustomed unjustly to wage private warfare against the faithful now go against the infidels and end with victory this war which should have been begun long ago. Let those who for a long time, have been robbers, now become knights. Let those who have been fighting against their brothers and relatives now fight in a proper way against the barbarians. Let those who have been serving as mercenaries for small pay now obtain the eternal reward. Let those who have been wearing themselves out in both body and soul now work for a double honor. Behold! on this side will be the sorrowful and poor, on that, the rich; on this side, the enemies of the Lord, on that, his friends. Let those who go not put off the journey, but rent their lands and collect money for their expenses; and as soon as winter is over and spring comes, let hem eagerly set out on the way with God as their guide."