The author deals with the text of an archival document discovered in the materials of the Second Kamchatka expedition led by Vitus Bering, in the collection of field notes of the expedition member, the German doctor and translator G. W. Steller. This fragment in Latin is a recording of a Yakut folk song of the first half of the 18th century. The purpose of this article is to introduce a previously unpublished archival text into scientific circulation by translating the text and describing its artistic features. As part of the research, the following tasks were set: to study the history of the text, give a description of the manuscript, transcribe and translate it into Russian and highlight the artistic means used. According to the fixation of Yakut folklore in the specified period is known to science the ethnographic work of J. J. Lindenau “Description of the nations of Siberia,” which contains the text of the algys ritual on the Ysekh holiday. There are also recordings of folk songs of northern nations performed by G. W. Steller, but this text has not yet been examined by folklorists. The work uses theoretical and practical research methods as: study of scientific works, the main research method is textual analysis, which uses the method of review, description, interpretation, connection, translation, decoding and analysis of the composition, artistic and visual means of the text. The author concludes that the ancient folk song has a developed syllable. Rhythmic alliterative verse, consonance of line endings close to varieties of rhyme, parallel constructions, constant epithets and comparisons as the main means of depiction demonstrate a fairly high level of development of Yakut folk poetry. The author sees the prospect of research in the discovery of similar texts of the specified period, which would allow more in-depth research in this area.