There is no written history of the Ossetes; indeed, information even from indirect sources is limited. The most important source from which we can derive knowledge about the origin and past of the Ossetes lies in the findings of historical-comparative linguistics. Following the guiding principle of Jakob Grimm ("Our language is also our history"), Vasili I. Abaev, the founder of modern Ossetic philology, has succeeded in elucidating the history of the Ossetic people by using the methodological principles of historical-comparative reconstruction and the study of linguistic contacts. Further sources are oral literary traditions and folklore in general. Before the results of linguistic study were known, the Ossetes were not aware that they do not belong to the autochthonous peoples of the Caucasus, much less that their language is a member of the Iranian Linguistic Family and that they are descended from the Alanic and Scytho-Sarmatian tribes.
The Scytho-Sarmatians, who lived in the vast plains of southern Russia in antiquity (especially in the Ponto-Caspian steppes), left few linguistic remains. The only direct evidence consists of several proper names in Greek inscriptions from the first centuries A.D. , some of which show phonological innovations that are characteristic of Ossetic but that are atypical of all other Iranian languages. The little we know about Scythian life we owe to certain classical authors, most particularly Herodotus. Aside from an Old Ossetic/Late-Alanic gravestone (see "Linguistic Affiliation"), we have no direct Alanic documents. Our scant knowledge about the Alans has been gathered from reports and references to them in contemporary sources, mainly Byzantine texts.
The Alans, who were a loose tribal confederacy in the Ponto-Caspian steppe region, are mentioned for the first time in classical sources in the first century A.D. During the period of the great migrations, and especially in the early fifth century, a segment of the Alanic tribes moved far west with the Goths, Vandals, and others. But the western Alans did not survive as an ethnic entity: they were totally absorbed by the autochthonous peoples. A comparison of the vast area of the eastern Alans in southern Russia and the limited area inhabited by the Ossetes in later centuries leads to the question, in which period did the late Alans (or early Ossetes) arrive in the region they currently inhabit? The main impetus to leave the plains of southern Russia and to retreat gradually to the mountains and valleys of the Caucasus must have been the the Mongol invasions. Despite stiff resistance, Alanic territory had been brought under the yoke of the Golden Horde by 1233.
After Tamerlane's conquest in 1395 the Alans totally disappeared from the northern foothills. After the Mongol period diverse Turkic and autochthonous West-Caucasian peoples and tribes forced the Alans to recede even further. In addition to these political reasons there were other motives for migrations, including the chronic lack of arable land, infertile soil, hunger, epidemic diseases, and avalanches and landslides that often devastated entire villages. Also, the strict traditional rule of blood vengeance not only caused the person directly involved to flee but sometimes obliged the entire clan to leave the hereditary residence. These migrations, which were common until the last century, ultimately resulted in all the Ossetes leaving the fertile North Ossetic plains. On the other hand, in the regions of South Ossetia and eastern Georgia, which have better climates and soil, the Ossetes have been present continuously since their first immigrations in the Middle Ages. After Russia annexed Ossetia at the end of the eighteenth century, thousands of Ossetes from the high mountainous regions started to recolonize the north Caucasian plains, hoping for amelioration of their basic living conditions under the protection of their new lords. Practically all the villages and towns founded in the present North Ossetia date from this period, whereas many settlements in southern and central Ossetia can be traced back to the sixteenth century (sometimes to the thirteenth or fourteenth century, or, in one case (Dmanisi), even to the ninth century. Information relevant to these issues consists mainly of the oral histories of the various clans and families; sporadic written documentation is available as of the eighteenth century. Until the beginning of the Soviet era, the Ossetes never succeeded in forming a state of their own. The various clans and rural communities were to a great degree independent of one another; they were bound politically and economically only to their various feudal lords. This situation changed in the 1920s when the South Ossetian Autonomous Region on Georgian soil (founded in 1922) and the North Ossetian Autonomous Region of the RSFSR (founded in 1924) were created. In 1936 the status of North Ossetia was upgraded to that of an autonomous republic, signifying greater independence.