The ideology of Pan-Croatianism created by Pavao Ritter Vitezović, who developed the ancient theory upon derivation of all Slavs from the Balkans, was a historical construction and a political program as a protest against long-time fragmentation of alleged Croatian historical and ethnic territories.
It is not surprising that Pavao Ritter Vitezović interpolated the whole territory of the Kingdom of Poland and the Grand Duchy of Lithuania into the Slavic lands, and furthermore, according to his ideological doctrine into a Greater Croatia.
The real ideological source for such a division of the whole world was the Slavic idea which decisively influenced Vitezović who recognized that all Slavs belonged to a single ethnolinguistic community.
The issue of national self-determination, the idea and goals of nationhood, and the methods and means for the attainment of such goals, were foremost in the thinking of 19th-century Serbian intellectuals and politicians.
The national dream of a free and united Serbian state began to be realized at the beginning of the 19th century, with two Serbian insurrections against the Ottoman authorities in 1804–1813 and 1815.
The “Idea of Union” in a single national state had deep roots in the historical development of political ideas among the South Slavs. This idea had several stages of development and the features of expression but, basically, the supporters of the “Idea of Union” primarily understood the Serbo-Croatian cultural, national and political cooperation, reciprocity, solidarity and finally unification as a “backbone” of any kind of a South Slavic state’s organization.