Review: The article considers the problem of analyzing the melodics of liturgical chants of the Russian Orthodox Church. The research object is the melodies which are the parts of the chants of the Christmas cycle and are used by archimandrite Matthew (Mormyl) in the Christmas Festive Triptych. The author studies the terminology traditional for medieval studies, folklore studies and general musicology to analyze one-voiced textual and musical compositions. In the author’s opinion, it is reasonable to apply the term ‘string’ to the smallest complete melodic structures closed in cadencies. For the fragments shorter than a string, the author introduces the term ‘micromodel’ proposed by Yu.N. Kholopov. The key research method used by the author is the functional method introduced by Riman and customized in the musical and theoretical tradition of Moscow Conservatory. The author also applies the elements of structural-typological method, which had developed in Russian ethnomusicology and was applied in the field of music medieval studies. Partially, the author also uses H. Schenker’s method of reduction tested within Kholopov’s music and theoretical concept. The multiplicity of the methodological aspect is one of the signs of the scientific novelty of the article. The author arrives at several conclusions. First of all, the melodic composition of regular chants is based on the principle of micromodels junction. Secondly, the essence of melodic micromodels comes down to the establishment of a local or a central modal basis. Thirdly, the junctions of melodic micromodels don’t rule out the presence of a significant pitch basis and inclination for tertian coordination. These conclusions prove that chants accumulate both archaic and relatively new style components. The author is the first to analyze the melodic of the Christmas Festive Triptych in its correlation with the pitch organization in Russian musicology.