What influence do the Romans have on the development of Christianity?

The Edict of Milan of 313 CE allowed for religious freedom and thus freedom from persecution. Eventually Christianity would become the dominant religion in the Empire replacing the worship of the Roman Pantheon and emperors. The church modeled its administrative structure on the divisions within the Roman Empire. Constantine founded an Eastern capitol in Constantinople which would eventually be mirrored by a split in the church between East and West. Christians adopted and transformed many of the holidays of pagan Rome in an effort perhaps to provide continuity between the old and new. They also adopted the architecture of the Romans, using the basilica and central plan church as the basis of the church and later the cathedral.