Faced with the shocking rise of the Arab Empire, Byzantines questioned if their use of religious icons was angering God. The success of the aniconic Arabs suggested that adopting a stricter, image-free worship might be the key to divine favor and military survival.
During the 5th and 6th centuries, celebrating the Nativity became a key way for the Byzantine church to counter debates about Christ's nature. The holiday served as a historical anchor, reinforcing that Jesus was a real person who lived, not a demigod or abstract spirit.
The two dominant powers, Rome and Persia, engaged in a decades-long, civilization-shattering war that left both empires fiscally and militarily broken. This created a massive power vacuum, allowing newly unified Arab tribes to expand with astonishing speed into unguarded territories.
Unlike the personal, lord-vassal ties defining Western European power, Byzantine society was built around a centralized, institutional emperor. Western visitors were awed by the grandeur but found the courtly protocols and lack of personal access to the emperor to be distant and arrogant.
Unlike Western Europe, where power was decentralized, Constantinople's strategic location naturally encouraged centralization. Its geographic dominance was so profound that it shaped both the Byzantine and Ottoman empires into highly centralized states, a rarity for the pre-modern world.
While early differences existed, the Christian East and West only began moving in truly different directions in the 11th century. Western reforms to make the priesthood more monastic—introducing clerical celibacy and papal infallibility—created practical divides that made the schism permanent.