The victory for the roman bishop was the fact that they had the material remains of st. peter. Jesus said you are the rock upon which my church will be built. The idea of succession or legitimacy is the critical idea that will animate so much of medieval art. Rome, who"s legitimacy comes from the twin sources of peter, who gets it directly from jesus, who passes it on to the next bishop of rome. The other form of legitimacy is the support and connection to the roma imperial heritage. Even though we no longer have any more of. Constantine"s churches we have archaeology descriptions of them. Monumental church building for which he was responsible. Built by constantine for the bishop of rome. Adoption of the basilica form, which was both practical (hold lots of people) relatively neutral building type, not associated with pagan temple format. Many basic features we are familiar with in church design.