THE BASIC PROBLEM addressed in this chapter will be a critical analysis of the research sources and the historiography of the research problem. Studying the historical sources and the extant historiography will allow us to determine both the volume and the quality of the information currently known, based on which our scientific research on the history of the Carpathian-Danubian space in the eighth and ninth centuries can be realized.

Historical sources are a set of information which constitutes the cultural heritage of mankind. Each work of historical research stems from analysis of the sources from which it can be developed. A separate critical analysis of narrative and archaeological sources and then their collation and dissection will allow us to support some conclusions about the historical realities to the north of the Lower Danube in the eighth and ninth centuries. However, we must consider the lack of internal narrative sources in reference to the history of the Carpathian-Danubian regions in the eighth and ninth centuries, while the number of external narratives is small and their content is often controversial.

Written Sources

In the absence of direct written sources, foreign internal narrative sources occasionally refer to the early medieval histories of the territories to the north of the Lower Danube, often having a very general or even contradictory character. Some Byzantine, Russian, Hungarian, and Oriental sources from the eighth and the ninth centuries describe certain events from the seventh– tenth centuries which have a direct or a tangential connection with either the territories to the north of the Danube or the people who lived in or passed through these areas. The style, the quality of the content, and the veracity of these early medieval sources have attracted the attention of historians for a long time. The most numerous narrative sources on the Carpathian-Danubian regions are Byzantine sources.

The Byzantine Writings

The Byzantine writings regarding the Danube regions in the second half of the first millennium are quite general. If for the sixth– seventh centuries Byzantine reports on the situation in the Lower Danube and with the Empire's confrontations with these tribes were frequent, owing to the “activism” of Slavic and Avar populations, Byzantium's interest in the Danube region dropped significantly in the eighth century.