The article analyzes the sources of the unpublished chronicle collection of the Trinity Collection no. 805, which is in the storage of the RSL. Two sources are identified — the main and additional. The sources are scrutinized from the beginning of the dated narrative to the chronicle article of 1209 (additional) and to the article of 1223 (main). The article shows that the compiler of the chronicle collection did not use an additional source in the area from 1036 to 1198. The article also analyzes the nature of the work of the chronicler with his main and additional sources.