The introduction to this book examines early city regulations established by different faith communities in the European and Mediterranean space of the ancient world. Christian Europe was distinguished by its loss of the certainties of Roman law and its replacement by customary law in the medieval period. Six main themes are considered in more detail: fire prevention, the conflict between public and private, environmental regulations, the impact of European empires and the Age of Absolutism, the enhancement of the beauty of townscapes, and the development of town planning. Concluding remarks examine the links between urban regulation and urban morphology.