In this thesis the author reviews the existing theories in the croatian historiography since the middle of the 19th century until the present day concerning the conditions in the western part of the Sava-Drava interfluvium from the end of the 8th century until the end of the 11th century. He analyses the works of croatian historians during that time; those works are mainly syntheses of croatian national history, usualy specificaly focused on the middle ages, but some are more narrowly focused works dedicated only to the interfluvium. The author notes which sources do these historians use and how, which theories do they take over from each other, and which methodological orientations and explanatory frameworks do they apply to the recorded historical occurences in order to integrate them into a big picture of historical development. In the end, the author proposes his own interpretion of the historical development in the area in question during the time period considered, and points out the directions in which further research should be taken.Three main issues were largely being discussed in croatian historiography: the issue of political affiliation of this area at a given time, the issue of this area's population's ethnic identity, and the issue of this area's ecclesiastical organisation. Historiography of the 19th and early 20th century largely focused on the reconstruction of a sequence of political events and changes of rule over the area in question with ecclesiastical organisation being studied mainly to indirectly provide pointers for political history. Existing narratives on those issues were in broad strokes mostly developed by the 19th and early 20th century historiography, used to study processes of long duration by the historiography in the second half of the 20th century, and in recent decades either relativesed by post-modernistically inclined historiography, or brought under reconsideration by reconstrunctionistally oriented historiography. Due to the scarcity of available sources significant changes in methodology and theoretical framework over the past 170 years didn't lead to major changes in historiographical interpretations. When it comes to the discussion of the ethnic identity, there were indeed great changes in interpretation over that time period, but they were affected primarily by meta-historical circumstances, namely by the significantly changed understanding of the contemporary croatian identity, rather than by changes in the historiographical methodology itself.Author proposes that in the future greater focus should be put on the study of socio – economic conditions in the area through greater scope of archaeological reasearch, as well as to develop further theoretical models of development based on comparative examples.