After the Habsburg empire rose to the position of a great power and successfully defended itself against the expansionist drives of Ottoman imperialism, both the population and the territory of the southeastern part of the monarchy began to increase. As a consequence of this expansion, an increasing number of Orthodox peoples were incorporated into the multinational empire on various legal bases. The Orthodox population of the empire certainly did not constitute anything resembling an undivided unit, whether in regard to the language which the people spoke or the length of time they lived in the area or belonged to the Habsburg monarchy. A real community of interests existed only insofar as folklore, tradition, and their common legal struggle for religious freedom were concerned. This was especially true of the Serbs and the Rumanians. During the course of their struggle to attain religious freedom a hierarchical social structure, dominated by the Serbian higher clergy, came into being which remained in existence for a long period of time.