New Perspectives on Ecclesiastical Architecture under Basil II: Reinterpreting the Octagon-Domed Churches of the 11th century

Octagon-domed churches, such as the Katholikon of Hosios Loukas and Nea Moni on Chios, represent some of the most innovative and distinctive examples of church architecture from the Middle Byzantine period. Although one of the earliest surviving examples of this rare architectural type are tentatively dated to the reigns of Basil II and his successors of the Macedonian Dynasty, its origins and significance remain subjects of scholarly debate. Some researchers have pointed to parallels with Armenian and Arabic architectural models, while others argue for a distinctly Byzantine origin or even connections to Early Byzantine prototypes. However, these theories often focus narrowly on the octagonal core and the use of squinches in the vaulting systems. Drawing on a new architectural survey of the Katholikon of Hosios Loukas, this paper revisits the debate by analyzing the full architectural form and construction of octagon-domed churches. Through a comprehensive and comparative approach—including parallels with contemporary Byzantine and Fatimid architecture—this study offers new insights into one of the most remarkable architectural innovations associated with the era of Basil II.