Prince G.G. Gagarin, famous for his illustrations for the novel by V.A. Sollogub “Tarantas”, devoted his life to embodiment of the novel’s idea of “settling the folk art” in Russia. The artist found the “folk art” in ancient Byzantium and began the realization of its “settling” in Russia from the Caucasus — first trying (though unsuccessfully) to establish a “special art school” there and then frescoing the Tiflis Sioni Cathedral in the Byzantine style. In developing the mural project, the artist abandoned his initial version, finding it, probably, nonconforming to the “pure Byzantine origins”, and followed the classical Byzantine church decoration system, aligning at the same time with the Sophia of Constantinople. Into the middle register of the altarpiece, the artist put the composition “Sending the Apostles to Preach”, which had a special significance forGeorgia surrounded by pagan peoples. In the Byzantine style of mural compositions, the artist sought to combine the “Greek Christian thought” with the “Greek pagan form”, translating the idea of ancient art Christianization, borrowed from French artists of the Romano-Byzantine direction. The artist called his method of Byzantine models treatment “free imitation”. While frescoing the Sioni Cathedral, he used, in particular, the miniatures of Byzantine manuscripts. This article is of interest because of the modern issue of religious art rebirth inRussia.