Final Answer:
The chain of events that culminated with the Photian Schism was set into motion by the rivalry between Pope Nicholas I and Patriarch Photius I.
Step-by-step explanation:
The Photian Schism, also known as the Photian Controversy, was a significant event in the history of the Eastern Orthodox Church that occurred in the 9th century.
It marked a period of strained relations and division between the Eastern and Western Christian churches.
The chain of events leading to the Photian Schism began with a dispute between Pope Nicholas I and Patriarch Photius I of Constantinople.
The primary source of conflict was the papal appointment of Ignatius as the patriarch of Constantinople, a decision that Photius and his supporters saw as an intrusion into their jurisdiction.
This conflict escalated into a series of accusations and counter-accusations between the Roman and Byzantine churches, with both sides questioning the legitimacy of each other's authority and practices. The issues at stake included theological differences, political power struggles, and jurisdictional disputes.
The Photian Schism reached its climax in 867 when Photius was deposed as patriarch of Constantinople by a papal council.
However, the schism did not end there, as Photius was later reinstated by a Byzantine council, leading to further tensions and divisions between the Eastern and Western churches.
In summary, the chain of events that culminated with the Photian Schism was set into motion by the rivalry and conflicts between Pope Nicholas I and Patriarch Photius I.
The dispute over authority and jurisdiction between the Roman and Byzantine churches led to a series of accusations and counter-accusations, ultimately resulting in a division that lasted for several years.