Treats ancient sites & monuments in the northern Campus Martius. For centuries during the Republic the field of the god Mars lay outside the city of Rome on its northwestern limit. Some political activities (for ex., public assemblies of citizens) & many religious activities (for ex., the cult of Mars) took place there. Pompey & Caesar began to alter the aspect of the land with a theater & its great colonnade, a hall of assembly & on the edge of the city a new forum with a temple. Emp. Augustus & his son-in-law Agrippa quickened the process of urbanization with a building program, combined with efforts to bring the Tiber River under control. Here is the story of the development of the terrain from the end of the Republic to the onset of church bldg. Illus.