<P> The Orthodox East perceived the Papacy as taking on monarchical characteristics that were not in line with the church's tradition . </P> <P> The final breach is often considered to have arisen after the capture and sacking of Constantinople by the Fourth Crusade in 1204 . Crusades against Christians in the East by Roman Catholic crusaders was not exclusive to the Mediterranean though (see also the Northern Crusades and the Battle of the Ice). The sacking of Constantinople and the Church of Holy Wisdom and establishment of the Latin Empire as a seeming attempt to supplant the Orthodox Byzantine Empire in 1204 is viewed with some rancour to the present day . Many in the East saw the actions of the West as a prime determining factor in the weakening of Byzantium . This led to the Empire's eventual conquest and fall to Islam . In 2004, Pope John Paul II extended a formal apology for the sacking of Constantinople in 1204; the apology was formally accepted by Patriarch Bartholomew of Constantinople . Many things that were stolen during this time: holy relics, riches, and many other items, are still held in various Western European cities, particularly Venice . </P> <P> From the 6th century onward most of the monasteries in the West were of the Benedictine Order . Owing to the stricter adherence to a reformed Benedictine rule, the abbey of Cluny became the acknowledged leader of western monasticism from the later 10th century . Cluny created a large, federated order in which the administrators of subsidiary houses served as deputies of the abbot of Cluny and answered to him . The Cluniac spirit was a revitalising influence on the Norman church, at its height from the second half of the 10th centuries through the early 12th . </P> <P> The next wave of monastic reform came with the Cistercian Movement . The first Cistercian abbey was founded in 1098, at Cîteaux Abbey . The keynote of Cistercian life was a return to a literal observance of the Benedictine rule, rejecting the developments of the Benedictines . The most striking feature in the reform was the return to manual labour, and especially to field - work . Inspired by Bernard of Clairvaux, the primary builder of the Cistercians, they became the main force of technological diffusion in medieval Europe . By the end of the 12th century the Cistercian houses numbered 500, and at its height in the 15th century the order claimed to have close to 750 houses . Most of these were built in wilderness areas, and played a major part in bringing such isolated parts of Europe into economic cultivation . </P>

Who initiated the reform of the christian church in the middle ages