Abstract: The object of this research is basilica as a sociocultural phenomenon. It represents one of the unique architectural forms, which epitomizes the harmony of beauty and utility. The authors thoroughly examine the evolution of secular basilica that sequentially manifests as a residential, judicial, and financial-economic building. During the process of “Christianization” of basilica, we could observe the adjustment of the archaic symbolic. The technological methods of ancient art, filled with the Biblical content, were implemented in mural paintings and creation of the mosaic floor. Thus, the subject of this research is the transformation process from a secular construct into the Christian temple. The methodological basis of this work consists in the following concepts, which allow revealing the multifacetedness of the phenomenon of basilica: theory of architecture; sociology of space and architecture; sociology of culture, religion; sociology of city. The conducted research determined the pragmatics and symbolic of the transformation of basilica from the secular construct to religious building. The authors make a conclusion on the complex mechanism of sacralization.