‘Introduction: defining paganism’ emphasizes that the notion of paganism, as generally understood today, was created by the early Christian Church. It was a label Christians applied to others, generally in a derogatory sense. The so-called pagans followed very diverse religious rituals and beliefs. Our knowledge of these has been shaped by the prejudices of those attempting to impose a new religion. Many of the sources were written retrospectively. There are many gaps in the literary record, where our understanding relies on trying to identify and interpret ritual activity from archaeological excavations. To understand the history of paganism is to recognize the fragmentary, distorted, and partial nature of the sources.