The scientific articles and studies of the proposed readership of the collection consider previously unexplored or poorly studied issues of the domestic history of the Lithuanian era, as well as an important range of problems associated with the genesis of the multi-ethnic state of the late Middle Ages - the beginning of modern times - the Grand Duchy of Lithuania. The interested reader will find in them the author's vision of answers to a wide range of problems that are being investigated for the first time or evaluated in a new way, as well as get acquainted with important sources that are being introduced into scientific circulation for the first time.