Historical development and politico-geographical characteristics of the border and borderland between the Republic of Croatia and Republic of Slovenia on umberak and in the Rivers Kupa and abranka Valley

Although natural basis cannot be a decisive criterion in defining borders, historical and politico-geographic development of the researched area reveals that natural bounds have been considerably used in the boundary demarcation between the Republic of Croatia and Republic of Slovenia. This can be also concluded for the analyzed sectors which are tied with the umberak Mountain and the Kupa and abranka River valleys. Besides natural favours (the boundary line runs over the top ridges of the mountain massif of umberak/Gorjanci, as well as along the river flows), one must point out the fact that it is adapted to spatial organization of the borderland. Therefore, the boundary line is subsequent and co-operative here. Evolutionally, the border and borderland developed from terra nullius, frontier, and, finally, since the 16th century, have become a boundary line on the rivers Kupa and abranka, and since 1816, on umberak. Consequently, in spite of disputes in particular historical periods about the researched area's state and property appurtenance, the border has a centuries-old continuity. This can explain that nowadays the quoted sectors are least disputable in the boundary demarcation of the two sovereignties.