The article deals with the verbal morphology in the monument of Mari writing “The Beginnings of Christian doctrine...” (published in Kazan in 1841). Among the earliest publications in the Mari language, this is one of the most voluminous texts, including Concise Sacred History and Catechism. The dialectal basis of the considered text is a Meadow dialect, at the same time the verbal morphology (mainly in the plural forms) differs significantly from the literary norm of the contemporary Mari (Meadow-Eastern) language. As a result of comparison with dialectological data, the correspondence of the verbal morphology in the monument to the conjugation in the western subdialects (Volga, Yoshkar-Ola) of the Meadow dialect is revealed. (These dialects turned out to be peripheral during the formation of the literary Meadow-Eastern Mari language in the 20th century. The verbal morphology of the literary language is based on the Morki-Sernur subdialect of the Meadow dialect and the Eastern dialect of the Mari language.) At the same time, the specific verb forms of Western subdialects of the Meadow dialect revealed in the monument and described in the article largely correlate with the conjugation in Western Mari dialects (Hill and North-Western), including the literary norm of the Hill Mari language. In general, the analysis of the verbal forms (with preliminary consideration of phonetic and vocabulary data) allows us to define the “The Beginnings of Christian Doctrine…” (1839 / 1841) as a most important early written monument of the Volga subdialect of the Meadow dialect and a valuable source on the historical dialectology of the Mari language. Keywords: Finno-Ugric languages, Mari language, Vol