The cross-in-square was one of the most common church forms in the middle Byzantine period (9th-12th centuries CE). This paper looks at how the architectural configuration of the cross-in-square developed, focusing on the threedimensional characteristics of all churches within Byzantine territories, unlike previous studies. These churches are classified according to their floor plan; horizontal shape and construction methods of supports; the arrangement of arches; and the support and arch connection methods. Two architectural groups emerge: the centralised church-like configuration, in which the arches are placed on the supports, and the two-direction configuration, where the arches penetrate inner walls.
