The aim of the research is the discovery of the path toward the “real synthesis” in the Prologue to the dramatic oratorio “Jeanne d’Arc au bûcher” by Arthur Honegger. An analysis of the composition, dramaturgy and musical language of the Prologue as the large-scale section generalizing according to the meaning leads to the understanding of the regularities of interaction of the structural elements of a dramatic play and the vocal-symphonic form. The author examines the semantic and compositional functions of dialogue as a special form of utterance characteristic for plays from drama theater and for the well-known varieties of liturgy music from the 10th-15th centuries (tropes, “holy dramas,” miracles, mysteries). As the result of the analysis the compositional peculiarities of the vocal-symphonic and verbal episodes of the Prologue are revealed, and definition is given to the semantic and musical-dramatic functions of its structural units connected with the musical manifestation of Claudel’s prayerful text “From the depths I have elevated my soul…” and the initial verse in Latin from Psalm 129 “De profundis clamavi ad Te, Domine.” The sound space of the Prologue to “Jeanne d’Arc au bûcher” reveals the dramaturgical versatility, and definition is given to the connecting compositional elements (the intertextual connections). Conclusions are arrived at about the temporal multidimensionality as a form of overcoming by the composer of the linearity of plotline narration, which made it possible for the composer’s contemporaries in the 1930s and 1940s to perceive the meaning of “Jeanne d’Arc au bûcher” as a relevant one; about the means of development of the contrapuntal musical texture in the vocal-symphonic composition of the Prologue to the dramatic oratorio; about the realization of the Bachian principles of “the counterpoint of affects” and the “centralizing force of the equal distribution of affects” in the composition of the Prologue. Most important were the observations of the dramatic rhymes in the composition of the Prologue; about the semantic significance of the liturgical sphere in the musical-dramaturgic development of the composition; about the spiritual dimension of time and eternity, disclosing in the Prologue to the dramatic oratorio the meaning of the phenomenon defined by Arthur Honegger as “real synthesis.”