Crusades affected the Eastern church adversely as it faced the brunt of the warfare.
Explanation:
During the crusades, which were called by the Pope in the west, the western knights would go and pillage the cities in the East and then other empires of the region would come and claim the lands again.
The Eastern Churches were stuck in between this constant warfare and faced the brunt of the crusades often because the crusaders could simply just go away again if they had to but the East was closer to the fighting spots.
