Book excerpt: "This book examines the octagonal churches of Late Antiquity from the origins of the type in the fourth century to its sixth-century culmination in its most famous example, the church of San Vitale in Ravenna. The buildings, limited in number and many overlooked in modern scholarship, served several functions including funerary oratory, martyrium, and cathedral, though most were martyr or memorial shrines. Beyond addressing questions of function, architectural design, structural solutions, chronology, literary sources, and architectural symbolism are also studied."--