The article considers the phenomenon of the academic school of Alexander Sergeevich Lappo-Danilevsky (1863-1919) in the context of the history of the St. Petersburg School of History. A hypothesis is put forward on the existence of two scientific communities different by the nature led by A.S. Lappo-Danilevsky. The first is a circle of scientists grouped around a scientific leader who shared with him the general methodological principles of scientific research. The second is a team of workers associated with a relatively narrow field (diplomatics of Russian private acts), which has consistently solved problems in accordance with the research program developed by their head and teacher. As emphasized in the article, with a change in the historiographic situation and social order for historical science in the post-revolutionary period and the death of A.S. Lappo-Danilevsky his research program could not be implemented, and the school as a scientific community essentially ceased to exist. However, the research facilities of A.S. Lappo-Danilevsky were determined by both the range of interests and the nature of the research activities of his students throughout their entire life path. The research focuses on the scientometric analysis of creative heritage as A.S. Lappo-Danilevsky, and his students (A.I. Andreev, S.N. Valk, V.I. Veretennikov and many others). In particular, the article considers the relevance of A.S. Lappo-Danilevsky and his school in modern scientific literature. The presented data clearly show the source study and historiographic nature of the most popular texts in modern science by the students of A.S. Lappo-Danilevsky, which allowed us to hypothesize the special role of his school in maintaining the professional traditions of national historiography.