The History of the Decline and Fall of the Roman Empire / Table of Contents with links in the HTML file to the two Project Gutenberg editions (12 volumes) · Chapter 269
Great Schism of 1054
The mutual excommunication of the Pope and the Patriarch of Constantinople in 1054 formalized the schism between the Latin and Greek churches, dividing Christianity into Roman Catholic and Eastern Orthodox branches.
Outcome
The schism created lasting division between Eastern and Western Christianity, complicating political and military cooperation against common threats.