The relevance of this study stems from the lack of a clear scholarly consensus on the identity of Abbot Marcellus Bezborody and the existence of controversial issues concerning the attribution of some liturgical texts, presumably written by Marcellus. It is known for certain that he composed services to the Venerable Barlaam and Josaphus of India, to the Venerable Nikita the Stylite of Pereslavl, and to Saint Nikita of Novgorod. Services to the Venerable Savva of Storozhevsky and Macarius of Kalyazin are also controversially attributed. The purpose of this article is to demonstrate the hymnographer’s working principles and his autonomy as an author by comparing the story of Barlaam and Josaphus with the liturgical text. The article presents basic biographical information about Abbot Marcel-lus. The service to the Venerable Barlaam and Josaphus is one of the most striking in the hymnography of Abbot Marcellus Bezborody. It reflects the extraordinary talent and originality of this 16th-century Russian hymnog-rapher. For comparison, we use Athanasius’s version of the Tale of Varlaam and Josaphus, which Abbot Marcellus Bezborody relied on when writing the service. This comparison demonstrates that it was Athanasius’s version of the Tale that was available to the hymnographer. Comparison of the text of the service with the Tale reveals the hymnographer’s idiostyle and demonstrates the originality of his work. The work of Marcellus Bezborody is highly unusual and original. His creative flourishing occurred during a period when imitative texts and texts borrowed from other authors were characteristic of Russian hymnography. Almost all liturgical services for the saints glorified at the Macarius Councils were composed in this manner. In this regard, Abbot Marcellus’s personality is exceptional in 16th-century Russian hymnography. Marcellus Bezborody’s talent was expressed both in the language of his writing and in various creative insertions into the text of the service, previously unheard of in hymnography and hagiography. These include, first and foremost, his introduction of an unusual acrostic into the canon of the service, a phrase dedicated to the service’s main characters, and the codification of the hymnographer’s name.