The monograph is a historical and ethnological study of the calendar holidays, customs, and rituals of a population that initially differed from other Bulgarians in its heretical Paulician beliefs and later in its new Catholic faith. The chronological scope of the study covers the period from the end of the 19th to the middle of the 20th century. To a large extent, these dates are arbitrary, as all known written evidence from earlier periods has been used to highlight the development of the calendar. The main materials on the subject were collected in the field and are the result of the author's many years of research in some twenty Bulgarian villages with a compact population of Bulgarian Catholics. This work is the first attempt to comprehensively present and analyze the festive and ritual system of the community in question. The book is aimed at ethnologists, cultural scientists, and historians, as well as a wider circle of readers interested in the traditional culture of Bulgarians and, in particular, its confessional, regional, or local variants.