The book examines the problem of the formation and development of the Bulgarian nation over the centuries. It analyzes the emergence and establishment of the Bulgarian nation in the 9th-10th centuries. Special attention is paid to the reflection of this process in the terminology of the old Bulgarian monuments from the 9th to the 14th century. The historical continuity of the Bulgarian nation during the Ottoman period is traced, which is expressed in the preservation of ethno-territorial unity, common language, material and spiritual culture. The process of preserving the national self-consciousness and its various manifestations is brought to the fore. Based on the analyzed source material, the author concludes that there is no difference between the terms "nationality" and "nation", which denote Bulgarians as an ethnic category over the centuries.