Christianity in the 13th century

The Eastern Roman (Byzantine) imperial church headed by Constantinople continued to assert its universal authority. By the 13th century this assertion was becoming increasingly irrelevant as the Eastern Roman Empire shrank and the Ottoman Turks took over most of what was left of the Byzantine Empire (indirectly aided by invasions from the West). The other Eastern European churches in communion with Constantinople were not part of its empire and were increasingly acting independently, achieving autocephalous status and only nominally acknowledging Constantinople's standing in the Church hierarchy. In Western Europe the Holy Roman Empire fragmented making it less of an empire as well.