Abstract: In the presented work, the object of research is the "Notes of the Decembrist I.I. Gorbachevsky", which are one of the most valuable sources on the history of the Decembrist movement, created by its participants themselves. They highlight the formation and development of such a Decembrist organization as the Society of United Slavs, which later joined the Southern Society of Decembrists. Written in exile in Siberia, these notes represent not only a source of factual material, but also an original concept of the secret society's development, and a retrospective "inside look" at the mistakes made by the conspirators.

However, Gorbachevsky's "Notes" are notable for another circumstance. Contrary to their well-established name in literature, we cannot unequivocally assert that their author was I.I. Gorbachevsky himself from among the Decembrists. The fact is that the first publication of the "Notes" – in the journal "Russian Archive" in 1882 – was presented under the heading "Notes of an Unknown Person from the Society of the United Slavs." The subject of the research in the presented work is the question of the authorship of the "Notes", which has no clear answer among historians today.
In this paper, we propose a solution to the problem of determining the authorship of the "Notes of the Decembrist I.I. Gorbachevsky" using machine learning methods. I.I. Gorbachevsky himself, as well as the Decembrist P.I. Borisov, are considered as possible authors. The novelty of the research lies in the fact that machine learning methods were used to determine the authorship of the "Notes". The authors trained four types of models to predict the authorship of each of the sentences in the Notes. As a result, most of the proposals of the "Notes" were assessed as written by Gorbachev. The largest percentage of offers, 69.2%, was attributed to Gorbachev by the Count Vectorizer + SVC model. The accuracy of all models exceeded 80% on average, while those based on BERT coding averaged close to 90%. The main conclusion of the work, therefore, can be considered that the "Notes" were more likely to have been written by I.I. Gorbachevsky than by P.I. Borisov. The methods used in the framework of the presented study provide another argument in favor of this version.

The code and dataset are available at the link: https://github.com/WLatonov/Gorbachevskiy_notes .