The article attempts to approach the scientific definition of that we traditionally define as the Church Slavonic language, often forgetting about those parameters that make it a specific phenomenon and in demand for more than a millennium. Moreover, these parameters are determined primarily by the textual nature of the Church Slavonic language. It exists in the form of texts, always ready to be reproduced, which represent the vocabulary and grammar of the entire history of its being. Apparently, the main hallmark of the Church Slavonic language is the presence of tradition as the main stabilizer of its existence, in contrast to the norm, which mainly preserves and ensures the unity of the language in modern times. The factual material is the data of several masterpieces included in the miscellany of the 15th century (No. 185) from N. Tikhonravov’s MSS collection of the Russian State Library in comparison with the “control” copies.