Horizontally Shifted and Vertically Superimposed Ancient Cities: Comparing Urban Histories of Chang’an and Rome

This article compares the forming and transforming process of two grand ancient capitals, Chang’an and Rome. Chang’an had been chosen as the capital of ancient China for many occasions. Repeated relocation had left Chan’an with a series of former sites widely distributed. By contrast, the urban cores of Rome had never moved faraway but remained within a confined area. It is observed that the historic city of Rome tend to be superimposed vertically instead of being horizontally scattered like Chang’an. This paired intriguing phenomenon makes the researcher wonder why and how these differences were made in the two millennium-old cities’ urbanization process. This study delves into the cause and mechanism of their unique development manners by comparing site selection procedures and the temporal-spatial configuration of each city respectively. Three aspects of proposition have been identified as critical to the cause of such dissimilarities, namely ideological thinking, practical consideration, and construction materials.