A rare literature plot has gained so much popularity in Europe as the one about the Nibelungs - old European heroes, whose deeds described by unknown authors are still researched by scholars. Russian philologists (V. Admoni, A. Gurevich, V. Zhirmunsky, M. Steblin-Kamensky, B. Yarkho) contributed to the study in the area with works about heroic epos and medieval literature and language. The Russian studies focus, however, not on the lay about the Nibelungs, but deal with narrower fields, like a structure, a language or features of an epos. European scholars, like A. Heusler and U. Schulze, undertook a comprehensive study of the topic. The first part of the article presented below discusses genesis of the Nibelungs’ story and the version of the Nibelungs lay which was spread in German lands in the Middle Ages and was put down as the Lay of the Nibelungs (Nibelungenlied) in the late 12th - early 13th centuries. The Lay is the most consistent story about the Nibelungs, and it is considered to be a profoundly studied text. Different elements of the Nibelungs’ lay can be found in the texts about the horn-skinned Siegfried (Das Lied vom hürnen Seyfrid). Though it is widely agreed that the story roots in the events of the 5-6th centuries A.D., there is still more to be investigated to understand the evolution of the plot and its elements. The Nibelungenlied has been research by many experts in the field, yet, some issues, e.g. oral/written basis of the text, archaic features and language peculiarities to name just few, need further investigation.