The article presents a schematic overview of the history of archaeological research of the underground mosque «Hilvet». The study is aimed at reviewing and analyzing the archaeological research of the underground mosque «Hilvet», one of the major centers of Sufism, which made a significant contribution to the flourishing development of Sufism and served from the ХІІ century to the first half of the ХХ century. Different results of archaeological investigations of the underground mosque «Khilvet», repeated reconstruction of the structure created difficulties in determining the exact history of the construction of the object. Specifying the terms and history of construction of such historical monuments allows us to generalize the functional and typological activities of religious underground structures. Expertise and analysis of archaeological data and data on the underground construction of «Khilvet» were carried out using the methods of historical comparison, type-inductive differentiation. The work aimed at revealing the meaning of scientifically refined opinions with an emphasis on methods of comparison and analysis was used in the systematization of data concerning the time and functional activity of the religious underground structure «Khilvet». Based on the results of repeated archaeological excavations that began in the first half of the 1970s and lasted for almost 30 years, it was possible to determine the exact construction date and condition of the original construction of the religious underground structure. The generalization of data from archaeological and historical research works is presented in scientific circulation with differentiation
