Omphalion is a specially marked place in central part of the temple. It originated from omphalos, the sacred stone at Delphi, which was considered as the “navel of the Earth”. In Christian church it was situated in the center of building under the dome. On the territory of Kievan Rus’ omphalia were found only in some monuments.
All the omphalia of Rus’ could be divided into two groups considering the used material and technology. The first group includes facings of the Tithe church and St. Sophia Cathedral in Kiev, the Savi­our Cathedral in Chernigov, St. Michael Cathedral in Pereyaslavl and Borisoglebskiy Cathedral in Chernigov. The composition in these monuments is made from many small pieces, and includes expensive prestigious materials: marble in the Tithe Churche, smalt in St. Sofia, and slate slabs inlaid with smalt in other three monuments. The second group includes facings in the churches in Galich principality: in the Saviour and the Annunciation churches in Galich, in the rotunda of Oleshkov and St. Paraskeva Church in Zvenigorod. The composition of all of these monuments represents concentric circles, inlaid entirely with glazed ceramic tiles with large figurative compositions in the centre. These two variants belong to two different traditions. The monuments of the first group are directly linked to the tradition of Byzantine mosaics. The monuments of the second group belong to the Galich architecture, which had its roots in Poland, where omphalia were made of large-scale ceramic tiles (facings in Gniezno and Trzhemesne). In Poland itself, this tradition also originated from the Byzantine Empire.
Thus the Russian omphalia existed within the Byzantine tradition, but in its two versions: direct and mediated. Both of them were variants of a common technology “opus sectile”.

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