The majority of the crusading army that set out from Venice in October 1202 originated from areas within France. It included men from Blois, Champagne, Amiens, Saint-Pol, the Ile-de-France and Burgundy. Several other regions of Europe sent substantial contingents as well, such as Flanders and Montferrat. Other notable groups came from the [[Holy Roman Empire]], including the men under Bishops Martin of Pairisand and Conrad of Halberstadt, together in alliance with the Venetian soldiers and sailors led by the Doge of Venice [[Enrico Dandolo]]. The crusade was to make directly for the centre of the Muslim world, Cairo, ready to sail on June 24, 1202. This agreement was ratified by Pope Innocent, with a solemn ban on attacks on Christian states.<ref>"History of the Church", Innocent III & the Latin East, p.370, Philips Hughes, Sheed & Ward, 1948.</ref>

The [[Monastery]] of Cluny in French Burgundy taught the high doctrine of the power of the Apostolic [[See]]. The Church was to be organized under strict discipline, and [[bishop]]s, [[priest]]s, and [[monk]]s had no rights of their own that were not derived from the pope, the unique source of ecclesiastical authority. In 1039 Cluny's [[abbot]] Odilo turned his [[monastery]] into the head of a monastic feudal system whose influence spread all over Europe. In 1055 the Monastery of Cluny captured the papacy. Pope Innocent III (pope during the Fourth Crusade) carried these Cluniac ideas about the position of the pope as the sole and highest authority in the Church.

With this background, and with the experience of the Great Schism in 1054, the papacy's position was that Byzantium was regarded as a rebel, a [[schism|schismatic]] or [[heretic]]al nation which should be brought back to order or eliminated.

The average European, especially those who lived in the northern territories and had no communication or knowledge of the [[Byzantine Empire]], were taught to believe that the Greeks were ungodly, a nation not worthy to bear the name of Christians. Two examples are:

#In the acccount of the Second Crusade (1147-49), ''De profectione Ludovici VII in Orientem (On Louis VII's journey to the East)'', written by Odo of Deuil, a chaplain to the French King Louis VII and later abbott of Saint-Denis, Odo explains the failure of the Crusade in terms of human action rather than as the will of God. He blamed the Byzantine Empire under Manuel Comnenus for the downfall of the Crusade. Odo's prejudice against Byzantium led historian Steven Runciman to describe Odo as "hysterically anti-Greek."

# Emperor [[Alexios I Komnenos|Alexius I Comnenus]] helped the First Crusade but was very cautious, signing an uneasy treaty and alliance with the Crusaders.

# Emperor [[Manuel I Komnenos|Manuel I Comnenus]] promised to help the Second Crusade and signed the same treaty with the Crusaders. However, he could not help because he was engaged in war against the Norman Prince Roger of Sicily, who had invaded Corfu. Manuel had also signed a treaty with the Turks of Iconium; the Crusaders, particularly the Franks, bitterly blamed him for their failure.

The fact is that Constantinople was always suspicious of these Western hordes, sometimes quite unruly, which were passing through its territory full of bigotry and fanaticism against the Islamic nations neighboring the Empire. Besides, the policy of the Byzantine Empire in handling the Moslems and keeping them away was quite opposite to the Crusaders' ideals and blind religious fanaticism. Historian Queller, quoting Runciman, says that "the concept of Christian War appears to be alien to the thought and personality of Jesus, and in fact, it was not looked upon favorably by the Greek Church."

Envy for the apparent wealth of the Greeks and perhaps the desire to share in some of the precious holy relics and treasure in the churches of the imperial capital was another motivation. The primary sources of the First Crusade speak of the awe the Crusaders felt when they first glanced at the Imperial City and the domes of [[Hagia Sophia (Constantinople)|Hagia Sophia]]; the feeling of inferiority is openly discerned as being at work in the Crusaders as a result.

More to the point, in both of the accounts of Villehardouin and that of the Crusader knight Robert of Clari (4th Crusade), the impression of the Crusaders is recorded. They were stunned by the unbelievable wealth and the treasure of the holy relics of Constantinople.

# There were bitter memories of recent Byzantine attacks on Westerners (in Sicily, West Greece(1098), and in Antioch during the First Crusade).

# 1149: The King of France Louis VII supported the suggestion that a European League should launch a new crusade against the emperor who was "Christian Only in Name." The capture of Constantinople should be the crusaders first objective. The Norman Roger of Sicily was in support of the idea, but his ally Pope Eugenius III was hesitant only because he feared the possible increase of Roger's power.