This book offers the first comprehensive study of octagonal churches from Late Antiquity (ca. 300-600 C.E.), tracing their origins to small funerary chapels of the fourth century. It analyzes physical and literary evidence for 35 such churches, culminating in the renowned San Vitale in Ravenna, dedicated in 547. Many of these structures no longer exist, while others are documented through nineteenth-century reports, recent excavations, or literary references. The study highlights the rarity of octagonal churches during this period, noting that most served funerary or martyrium purposes, marking the burial sites of Christian martyrs. A few functioned as memorials at significant Christian locations, such as Bethlehem and Capernaum, with the Great Church in Antioch serving as a cathedral. Numerous architectural drawings and color photographs complement the analysis. In the sixth century, some churches were retrofitted for regular liturgical services, and new designs integrated martyr shrines with standard liturgy. The design chapter discusses the octagons' dimensions, typically based on divisible diameters and simple proportional schemes like 2:1 and 3:2. The San Vitale chapter illustrates these principles, identifying the Byzantine foot as the measurement unit. This work is aimed at scholars and students of Byzantine and Late Antique architecture, as well as those interested in broader themes in architectural history, Byzantine
