The links of Middle Byzantine domed octagonal churches with contemporary constantinopolitan architecture

The almost sudden emergence of domed octagonal churches in the first half of the 11th century with a strong emphasis on the central space and the use of squinches in the dome transition, together with their known existence only in a somehow confined area, the architecture of which is defined as Helladic Paradigm; led scholars of Byzantine architecture to question the origins of the plan-scheme. Although a significant number of data indicates a contemporary Constantinopolitan link for the domed octagonal design, there are not any surviving examples of the plan-scheme in the capital or in its close environs. On the other hand, in the Middle Byzantine architecture of the capital, it is possible to trace the existence of some design principles, spatial arrangements and structural features which are also employed in the domed octagonal churches. This study surveys the similar architectural solutions in Constantinople in the same period through four ecclesiastical structures which were built in the 11th century, excluding the conjectural discussions regarding the origins of the plan-scheme. The first two of the buildings which are examined in the thesis are the Church of Theotokos Peribleptos in Psamathia and the Church of St. George in Mangana, the remains of the substructures of both of which are fragmentarily preserved and documented. Their relationship with domed octagonal churches is reconsidered using both the primary sources and archaeological data. The architecture of both churches is compared with the Catholicon of Hosios Loukas in Phocis in particular since it is argued that they share some specific characteristics of the complex domed octagonal design. Furthermore, the emphasis on the experimental architecture of them in Chronographia of Michael Psellus also strengthens their connection with the origins of the innovative design of the octagonal churches. The fact that both of these imperial foundations are built in the first half of the 11th century in Constantinople also underlines the metropolitan impetus on the emergence of the plan-scheme. Other two structures in the thesis imply the now-lost existence of the plan-scheme in the surroundings of Constantinople in the second half of the 11th century. One of them is Panagia Kamariotissa Church on Chalke which is located amidst a military site today. Even though it is in a relatively good state of preservation, it is hardly accessible to scholars. Although it could not be visited and properly documented for the thesis, unpublished architectural survey drawings which were done in 2000 are used for further interpretation. The church is in tetraconch design with curvilinear niches which are placed diagonally in the four dome-supports. These niches create an octagonal base on which the dome stands. Because of this uncommon architectural feature, the church on Chalke is regarded as the earliest known pseudo octagonal church, which is a variation of the domed octagonal design. Lastly, the surviving data about the non-existent Hagios Spyridon Church in Selymbria which was preserved until the first quarter of the 20th century, indicate that it was actually built in simple domed octagonal plan-scheme. Besides, some architectural elements which were probably belonging to Spyridon Church provide evidence for the use of a rarely encountered interior arrangement which is also found in the Catholicon of Nea Moni on Chios, the first known simple domed octagonal church. It can be asserted that it was constructed possibly as the first church in the simple domed octagon design after the Catholicon in the late 11th century. Along with this line, it is possible to argue that the designs of the church in Selymbria and Nea Moni are linked directly or through an unknown structure in Constantinople which had an impetus on both. In the last analysis, reexamination of the above-mentioned 11th-century Constantinopolitan churches in terms of their link with the octagonal design shows that the same spatial and constructional ideas were also in circulation among the master builders and architects who were actively working in Byzantine capital. Additionally, the existence of a simple domed octagonal church in the vicinity of Constantinople is important for the possible influence of the center on the origins of the plan-scheme and its spread in the area. The innovative ideas in art and architecture in the capital were generally produced by Constantinopolitan workshops, but in a lesser degree some of them were also generated in provincial contexts and imported into the capital. Whichever the case may be, the study provides further evidence for the existence of octagonal churches in Constantinople and even a metropolitan influence on the emergence of the plan-scheme, although there are not many surviving examples in and around the city.