SVS Press has publishes another invaluable volume for the church historian in "The Christian East and the Rise of the Papacy" by Aresteides Papadakis, since it focuses on the much-neglected area of Byzantium. Papadakis' essential thesis is that the final split between the Roman Catholic and Eastern Orthodox churches did not come about in 1054, with the mutual anathemas, but in 1204, when crusaders sacked Constantinople. The factors that led to this were a stronger papal control over the church, and an imperialism during the crusades, wherein Eastern Christians were the victims more than Muslims were.
In the 11th century, the clergy were appointed by feudal lords in Western Europe, which resulted in all kinds of simony and corruption. "It was undoubtedly lay control of ecclesiastical structure that made possible the purchase or sale of virtually every clerical grade the general rule by the tenth century. Simony became in fact unavoidable once clerical offices began to be treated like secular appointments." (p. 23) Most priests were married, and the church property simply went to their children. Further, the papacy itself was a puppet of the German emperor. A reform movement emerged in response to these abuses, led by Peter Damian and Leo IX. First, they wanted to enforce mandatory celibacy to prevent church property to pass into the hands of the priests' children. Second, they wanted to make the papacy independent of secular political control by electing the popes through conclaves made of cardinals. The College of Cardinals, which survives to this day, was Peter Damian's idea. "Significantly, the belief frequently expressed by medieval authors that the college of cardinals was the pope's supreme advisory body and, as such, was an imitation of the ancient Roman senate, was first articulated by one of the most uncompromising of the early Gregorians, Peter Damian." (p. 35-36) Finally, they wanted to end lay investiture.
In the context of the newly-powerful papacy and a suspicion towards Islam, the crusades were launched. The ostensible purpose of the first crusade was to re-capture Jerusalem from the Muslims and help the Christians of the east. Unfortunately, this is not exactly what happened. The papacy wanted to bring the Eastern Christians under its control, evoking the Donation of Constantine and historically specious arguments. Many in the western church saw the easterners as traitors. After the first crusade, parallel Latin jurisdictions were set up in areas where there were no Latin Christians before. This continued through the crusades in the Middle East (to say nothing of the Northern Crusades). Papadakis does not neglect to note that the idea of violence in the Western church had deep roots. "The theoretical justification for just war or even holy war outlined above- expressed for the first time by Augustine- was to have a lasting influence on the ethic of warfare in Western Christendom...Later papal reformers, insofar as they viewed their opposition to feudal power as a struggle against heretics and schismatics, or even excommunicates, were to find in these ideas a number of useful weapons...The belief that the Church had the power to authorize violence against heretics was in fact expanded to include pagans, as pope Gregory I's encouragement of such activity for the purpose of evangelization in the sixth century illustrates. This principle of forcible conversion may have inspired Charlemagne's later campaigns against the pagan Saxons." (p. 80) Many on both sides, however, still thought that some form of reconciliation was possible.
With the sack of Constantinople in 1204, any hope for re-union was effectively destroyed along with the city. The purpose of Fourth Crusade was to conquer Muslim Jerusalem via an invasion of Egypt. Instead, the crusaders diverted to Constantinople and took the city. The sacking was brutal, even by medieval standards. It did not happen in a vacuum or in a fit of mob rage, however. The constant rhetoric that people were hearing in the west was that the Byzantines were heretics, schismatics, and traitors. "Such observations came to be viewed as Gospel truth by the end of the century. They had become so popular by then that the diversionary assault on Constantinople, when it finally did come, was accepted with little hesitation. The fatal attack was rationalized by everyone involved by the belief that the Byzantines were already heretics. For the fourth crusade apparently the schism had been in existence for some time." (p. 103) Although there were attempts at reconciliation after 1204, in the Councils of Lyons and Florence, they ultimately failed. In addition, though Constantinople was eventually returned to the Byzantine Empire, the sacking of the city so weakened the Empire that they were unable to withstand the Turkish assaults in the 15th century. "Conceivably, the systematic Ottoman occupation of Asia Minor and the Balkans would not have been so effortless had the empire been able to maintain its territorial unity and strength after the fourth crusade." (p. 410) Although the Christians in the Ottoman Empire were allowed to exist and practice their religion, theological/cultural development would come to a halt, and they would be cut off from communication with their Western brethren until the fall of the Ottoman Empire. Highly recommended for students of church history.