The invention of the Christian church was one of the brilliant--perhaps the most brilliant--solutions in architectural history. This was achieved by a process of assimilating and rejecting various precedents, such as the Greek temple, the Roman public building, the private Roman house, and the synagogue. The Early Christian period saw the growth of Christianity, effectively an underground Eastern mystery cult during the first three centuries AD. It was established as the state religion of the Empire under the successors of Constantine. Ecclesiastical administration set up within the framework of the Roman Empire. Little change in social and economic order. Gradual split between Eastern and Western Empire in state and church. Political and economic breakdown of the West, ending in barbarian invasions.