The basilica type is characteristic for the Christian architecture of the Latin circle and the central type for the Greek Christian.
The central part of the church is a space with a square plan, located in the nave and delimited by four robust pillars. The square is inscribed with a circle, which is the base of the dome spanning the church's main space.
The dome is supported by four pendentives (a kind of vault in the shape of a spherical triangle) - a solution typical of Byzantine architecture. Thanks to them, the massive dome with a diameter of 31 m (101 ft) and the height from the floor to the highest point - 55.6 m (182,5 ft) - optically loses its weight and becomes delicate.
From the east and west, below the dome, two half-domes adjoin the walls of the nave, supporting the central dome and covering the remaining space. Additionally, the pillars supporting the columns are reinforced with massive buttresses.
