Schism or family quarrel?
Hindsight, as the saying goes, is 20/20, and as we look back on the events of 1054 we can detect a decisive rift between Christian West and Christian East. However, the original terms of the Schism were limited to a dispute between Rome itself and Constantinople itself, and there are signs of more closeness between other parts of Christian East and West during this time. For example, Western pilgrims to the Holy Land were still given Holy Communion by the Greek clergy at the holy places. In the minds of many Christians, the squabble between Old and New Rome might have been merely another family altercation of the sort which had happened before and could always happen again. Yet the Schism in 1054 was permanent, for several reasons:
Filioque: Before 1054, the filioque caused disturbances, but in the main the Popes stood firmly against it, which pacified the Eastern churches. After 1014, filioque invaded Rome itself and the Popes began ordering the Easterners to adopt it. In 1054, this was the only dogmatic issue on which Rome and the East could not at all see eye to eye. Soon after 1054, Western theologians hastened to justify the Creed change with a number of "dogmatic" opinions, cementing the mistake in place.
Papal Power: As we saw earlier, East-West unity was severely threatened in the 9th century by Pope Nicholas I’s power dramas. After a century of dormancy, a series of 11th-century Popes stirred up the unholy fires of ambition afresh, and Papal power reached its peak in the 13th century. At Rome, the papal pretensions finally grew so ingrained that no moderating voice could be found to reconcile Pope to Patriarchs.
Disparity of Customs: The Greeks were already wary of certain liturgical innovations adopted at Rome, such as unleavened bread (1053) and single-immersion baptisms (in some regions). This suspicion was often leveled against the West indiscriminately, and in some circles had risen to nothing short of a fever pitch. Ancient Western customs, such as omitting the singing of "alleluia" during Lent and the manner of preparing the bread and wine for the Eucharist, etc., were bitterly attacked.