The author in his study examines the peace-treaties that closed the First World War from the legal point of view. These Treaties besides the rights ensured to all the inhabitants or citizens, directed the rights ensured to citizens belonging to ethnical, religious, or language minorities or certain citizens belonging to religious minorities, or certain ethical or language minorities. Later, he analyses the individual and collective rights of national minorities, that the Treaties do not declare unanimously that these rights refer only to the rights of the minorities or that they refer to minorities collectively (they even do not state resolutely who are the representatives of the minority). We even face rights that concern only individuals belonging to the minority (personal liberty), and there are even rights that concern minorities as a whole (right concerning autonomy). In the case of Czechoslovakia the right for autonomy e.g. concerned only the Ruthenian nationality and not the whole nation of the Carpathian territory. The minorities according to the Treaties could not be subject to the international right, only their objects, i.e. the minorities did not have any rights to propose their complaints to the League of Nations. The minorities could call attention of the Council to the breaking or the dangers of the orders of the Treaties of Minorities, but it was not a right, only a possibility. Consequently, the author examines the issues of nationality of minorities, because the vast majority of minority rights concern citizens that belong to one of the ethnic, religious, or language minority. And this was under the protection of the League of Nations. Although, the League of Nations examined the complaints of the minority a rather slowly with which the minorities were not satisfied.