Which was a major cause of the 11th-century schism between the orthodox church and the catholic church ?

The Eastern Christians spoke Greek where the Western Christians spoke Latin. Where the Eastern Church's administration was governed by a group of bishops (i.e., Constantinople, Alexandria, Antioch and Jerusalem) which shared a common language and cultural background, the Western Church's administration was governed by a single bishop: the bishop of Rome. All these factors led to some basic theological differences between the Orthodox Church of the East and West. 

Unfortunately, by the eleventh century A.D. the differences between East and West became great enough to cause a separation of the One Holy Orthodox Catholic Church. The Eastern Church became known as the Eastern Orthodox Church and the Western Church became know as the Roman Catholic Church, for it was governed and administered by the bishop or Pope of Rome. Again it must be emphasized that there were many factors besides theological ones which led to the schism of the one Christian Church.