Rome conquered Greece by military force (146 B.C.); meanwhile Greece made a more thorough conquest of Rome by ideas. While there were many significant differences in language, customs, education, and institutions, yet religiously they were united in a twofold way: (1) by a common paganism, and (2) by Christianity. The East was philosophical, contemplating, metaphysical, and keen in discrimination; the West was practical, legal, and aggressively conservative. This difference in temperament was destined to have marked historical results.[265:1] While the West produced the mediæval Church, the East remained comparatively stationary. When the seat of Roman empire was removed from the Eternal City to Constantinople in 330, it appeared as if the eastern world had again become triumphant. A divergence between the churches of the East and the churches of the West, can be detected in the Christian philosophy and Christian theology from the beginning. The differences became more pronounced as the years passed by. The Arian Controversy (see Ch. IX.) produced the first crisis in the breach between Roman and Greek Christianity. The victory won by the West over the East was only temporary, however, because in the end the powerful state was arrayed on the side of the Eastern Church. The adoption of the "filioque" clause to the Nicene Creed by the Western Church, gave mortal offence to the Greeks. The doctrine of purgatory was another irreconcilable difference. Theoretically the Church was still united: (1) in the Emperor who ruled both wings of the old Empire; (2) in the Pope who pretended to rule over the East and the West; and (3) in the fundamental Christian principles. While there were still many resemblances, the differences were also becoming well marked in Church polity and organisation, in dogma, in rites and ceremonies, in monasticism, and in missionary activity. Among the matters in dispute was the growing differentiation of opinion on the question of the marriage of the clergy. The Roman Church was much more strict in the enforcement of celibacy. The two churches refused to agree on the same universal councils, and, of course, as a result, accepted an unequal number of canons as valid. Neither could they agree on the proper day for celebrating Easter. There were also many minor differences in reference to such trivial things as the tonsure, the beard, priestly garments, and Lent. Another stumbling-block was set up when the dispute arose over the sacramental bread in the eucharist. In the ninth century the Western Church departed from the earlier practice of using fermented bread and insisted on the unleavened bread as in the Jewish passover.