The paper considers the core characteristics given to circumscribe a group of grammatical texts used for missionary purposes in catechesis and bible translation. It is argued that the given definition is too broad to be used in the linguistic sense of a text type. In a next step the historical intentions of grammar writing before the age of historical linguistics are considered and it is argued that grammarians before the beginning of the 19th c. are looking for the “pure” source (called “language” or “idiom”) of the existing vernacular languages (called “dialect”). Ludolf’s grammar is a good example for this intention: its author writes a grammar of the Russian vernacular, considered as a conceptual oral “dialect” used for mutual understanding, in order to prepare for the knowledge of “Slavonic” as a conceptual written language used to reach an universal understanding of different cultures on a level of theological learning. Ludolf’s Russian grammar should be understood as the propaedeutic preparation for Church Slavonic.