Аннотация:The swift development of an oral Christian tradition that occurred after the official Christianization of the Roman Empire actively promoted the evolution of the liturgical year. Poetic extracts of the homilies became texts for hymnographic treatment as well as for the various categories of the major (the kontakion and the canon) and minor (troparia, stichira) liturgical forms. Correctly dating the homilies permits us to clarify the dates of the establishment of various liturgical feasts and indirectly, the collections of liturgical hymns. This study attempts to explain several questions related to the homiletic production of an enigmatic priest, Leontios of Constantinople, especially the calculation of the date of his homilies. The most accurate hypothesis for establishing this date at the end of the fourth century or the middle of the fifth is derived by applying dogmatic criteria to the problem, something which has not, until now, been taken into account.