The article examines the Russian period of the life and work of the Russian and Yugoslav historian, legal scholar and literary critic Aleksandr Vasilievich Soloviev (1890–1971). Up to now, the legacy of his emigration period (from 1920) has been studied in considerable detail. During this time, while teaching at the Universities of Belgrade and Sarajevo in Yugoslavia, and later at the University of Geneva in Switzerland (from 1952), he composed numerous works on the legal history of the southern Slavs during the Middle Ages, as well as on the history and literature of medieval Russia. However, his Russian years have remained overshadowed by these achievements. This article attempts to fill this gap. It characterizes the Faculty of Law at Warsaw University, where Soloviev studied, noting the infl uence of professors F.F. Siegel, I.A. Malinovsky, and E.V. Spektorsky on his education, with a special emphasis on Siegel’s role in fostering Soloviev’s interest in Slavic history and law. Based on unpublished archival documents, it is shown that Soloviev’s master’s preparation coincided with the introduction of a new system for awarding academic degrees in Russian legal history at the end of 1915, leading to changes in the system of master’s examinations for professorial fellows. The article introduces internal administrative documents of Warsaw University (1914–1917), which demonstrate the development of master’s training in Russian legal history. For the first time, early source studies by A.V. Soloviev from 1916–1917 are characterized. One of these studies deals with a unique Galician- Russian charter from 1414, discovered by Soloviev. Another article discusses the newly discovered translation of the Lithuanian Statute. Soloviev concludes that this translation had a signifi cant influence on the Sobornoye Ulozhenie of 1649. Additionally, the author has established Soloviev’s authorship of an article on American universities, published in the journal “Issues of Pedagogy” in 1913. Thus, Soloviev is presented as a student, professorial fellow and novice lecturer at the Warsaw/Don University.