Musicology Annotation << Back Oratorio «Isaac» at St. Thomas Church: to the History of Music in Leipzig in the Middle of the 18th Century Shabalina Tatiana The article is devoted to a source of a Passion Oratorio «Isaac» found in the National Library of Russia which gives evidence of a work performed in 1754 at Leipzig St. Thomas church. It is shown, that the original printed libretto reveals a hitherto unknown fact of the music history of the city and belongs to the oratorio by Johann Heinrich Rolle (1716–1785), presented on Good Friday of that year. All the details of the found source are studied; its text and comparison with the score of the work kept at the State Library of Berlin are analyzed; basing on this research the conclusion about the version performed in Leipzig under Gottlob Harrer (1703–1755) is drawn. The chronology of performances of Passions and Passion Oratorios in the period covered the late years of the life of Johann Sebastian Bach (1685–1750) and activity of his direct successors is elaborated that allows to trace essential changes in the history of musical traditions development in Leipzig in the 1740–50s years. The meaning of the found source for our knowledge of new tendencies in the German musical culture of the mid of the 18th century and its relevance in the context of increasing interest of researchers and performers in the work by successors of the great master are underlined. The libretto was presented in the Bach-Jahrbuch 2020, the current article introduces it for the fi rst time into the Russian musicology and contains new materials in comparison with the previous publication. Keywords: Passion Oratorio, libretto, Johann Heinrich Rolle, Gottlob Harrer, Johann Sebastian Bach, the National Library of Russia. DOI: 10.25791/musicology.9.2024.1393 Pp. 16-24.