Edward Bispham & Christopher Smith 
Religion in Archaic and Republican Rome and Italy [PDF ebook] 
Evidence and Experience

As Rome extended its influence throughout Italy, gradually incorporating its various peoples in a process of Romanization and conquest, its religion was extensively influenced by the cults of religious practices of its new subjects and citizens. It was a period of intense religious ferment and creativity. Roman religion, controlled and determined by religious and political functionaries who mediated between humans, had centred on a select pantheon of gods with Jupiter at its head. It was a religion in the process of becoming the servant of the state, however genuine its priests and votaries might be. Understanding the dynamics of religious change is fundamental to understanding the changing culture and politics of Rome during the last five centuries B.C. Religion in Archaic and Republic Rome and Italy tells that story.