The onset of the Iron Age as a whole can not be determined. The technology of its production and manufacturing of consumer iron goods was adopted over a long period in different places. On a planetary scale beginning of this era lasted until the time of great discoveries. In the Near East, where attempts to use the iron backs to the III millennium BC, improved methods of production and processing of iron lasted more than a thousand years before it found a more or less widely using. Only with the 15-13-th century BC the metal begins to be used there first for jewelry, and then to make weapons and tools. After two or three centuries iron metallurgy becomes known in the Balkans and the Danube basin. Hence and, obviously, also through the Caucasus, it came to the south of Eastern Europe in the 8th century BC and in Central Europe later. The slow uptake of new metallurgical technology does not lead to fundamental changes in the material culture of the time. Therefore, one and the same culture can be referred to as the Late Bronze and Early Iron Age. Greater importance for the emergence of a new culture had social-economic development of individual ethnic formations and migration. Accordingly, the study of the Iron Age ethnogenetic processes will be carried out not on the basis of the achievements of archeology but linguistic methods and has to be confirmed by the results obtained by archaeological data.
When it became known that before the Iron Age the majority of Indo-European peoples have already left Eastern Europe, and the ethnicity of individual archaeological cultures remained uncertain, continuing research of ethnogenetic processes by graphoanalitical method had needed a reliable reference point. As that was taken the scheme of the kinship of Slavic languages. The study of Baltic languages cannot give results because of their small quantity. Only two of them – Latvian and Lithuanian – remained be "living" tongues at present. Yet the vocabulary of Prussian language restored by linguists can be still added to these languages, but the obtained model of these three languages cannot be localized on natural areas of their uprising because of the small number of knots. In any case, the model will have the form of a triangle which can be placed on a geographical map in any way. Not much information was kept about the Thracian language or its dialects. The same can be said about the language of the Scythians. Consequently, we have no other material for the study concerning the 1st mill BC except the vocabulary of the Slavic languages. The first such study by means of the selected vocabulary of modern Slavic tongues has been maid yet at the end of the eighties and its results have been published in a linguistic magazine (STETSYUK V.M., 1987). However, the results of new research were already known yet then. This research has been made by means of the other database, namely by the representative selection from Slawski's and Trubachev's etymological dictionaries of the Proto-Slavic-language (TRUBACHIOV O.N. Ed., 1974 – ), SŁAWSKI F. 1974).
Unfortunately, the limited volume of the magazine article did not allow to publish the results of both researches. Consequently, the results of the previous research have been chosen for the publication, although, it would be necessary to bring some correction to the model of Slavic languages concerning the Russian language according to the results of the second research. This was be done some years later (STETSYUK VALENTYN., 2000).