This is the 7th blog in this introductory series to the Orthodox Faith. The First blog is The First blog is Orthodoxy in the World & Light to the World. The previous blog is Orthodoxy in the World: The Imperial Church.
The Age of the Councils determined for future generations of Orthodox that worship was the normative way in which one experienced and understood God. The Council period focused the theological debates on correct ways of worshiping. Thus theology and liturgy became tightly woven together. So too in this period as doctrine became defined also church governance became fixed. The power of patriarchs and bishops and priests was defined, and the shape of diocesan and patriarchal authority made permanent. Forms of the spiritual life – the monastic ideal, and a vision for Christian society, all became established and accepted by the Church.
Following the age of the Councils, Orthodoxy went through a growth period, as its form of Christianity spread. Byzantium was at the same crossroads of cultures and continents as the entire Middle East is. The Roman Empire centered in Constantinople attracted much attention from world powers. Persians, Arabs, Bulgars, Rus and finally the Turks all came to claim imperial power. The Byzantines had a number of centuries of success against such invaders and did export their religion to other regions. Eventually the Bulgarians and the Rus did embrace Orthodox Christianity, and these new nations came to shape their own cultures and kingdoms and religion on what they saw in the Byzantine Christian Empire.
Simultaneously though as Orthodoxy was spreading to the north and northeast, the seeds of destruction for Byzantium were being sown. Weakened by centuries of warfare with external enemies, and internal strife of competing factions, the Byzantine Empire was beginning to crumble. Arab Muslims took over much of the Eastern portions of the Empire. Then in 1204, Christians from the West, in the form of the 4th Crusade, captured the city of Constantinople from the Greeks. This event so seared the minds of the Orthodox that most Eastern Christians count this as the official split of Roman Catholicism from Orthodoxy. In 1453, the Ottoman Turks once and for all defeated the Byzantines, capturing Constantinople and turning it into a capital city of Islam. The Christians throughout the Empire fell into the period of Turkish captivity. The Golden age of Greek Christianity had come to an end.
Orthodoxy to the north, beyond the reach of the Turkish invaders, however thrived. The Russian Empire embraced Orthodoxy and its mythology and saw itself as the new imperial defenders of Christianity. By 1900 the Russian Orthodox Church boasted a membership of 100 million, the largest national church on earth.