Final answer:
The Great Schism of 1054 was primarily caused by linguistic and cultural differences and disputes over the ecclesiastical authority between the Eastern and Western churches, leading to their formal separation into the Eastern Orthodox Church and the Catholic Church.
Step-by-step explanation:
The two main causes of the Great Schism of 1054 were the cultural and linguistic differences between the East and West and disputes regarding ecclesiastical authority and practice. Cultural and linguistic distinctions had created a divide between the Latin-speaking West and the Greek-speaking East. The Western church operated in Latin and enforced clerical celibacy, while the Eastern church used Greek and allowed priests to marry. Additionally, the West elevated the pope as the sole authority, whereas the East maintained a system where patriarchs were considered to have equal authority.
Many attempts were made to bridge the gap through dialogue and reform movements, but they often accentuated the differences. The tipping point came when the pope’s chief representative excommunicated the patriarch of Constantinople after feeling that the patriarch was neither cooperating with nor recognizing the papal embassy. The patriarch responded in kind, excommunicating the pope's representatives. Thus the cultural and ecclesiastical rifts culminated in the formal separation of the Eastern Orthodox Church and the Catholic Church.