A systematic, calendar-based study that follows the ancient Roman year and treats each public festival in turn, reconstructing rites, liturgy, and the religious calendar of the Republic. The author compiles and comments on entries from ancient fasti and literary sources, explains the mechanics of the Roman calendar and its cycles, evaluates competing scholarly interpretations, and notes numismatic evidence. Sections proceed month by month, offering concise descriptions of ceremonies, their probable origins, and the ambiguities and gaps in the record; appendices supply coin notes, indices, and collected references for further research.