After gaining its independence in the Russo-Romanian-Turkish War, 1877-1878, Romania chose as a security solution the alliance with the Central Powers (October 1883), alliance to which Italy also adhered in May 1888. Strategic, political-diplomatic and economic reasons, but especially the fear of Russia shaped this option. Towards the end of the century, in the mind of the Romanian decision-makers the fear of Russia was replaced by the combined fear of Russia and Bulgaria, and this given that the Bulgarian nationalism centered on the territorial expansion in Macedonia became increasingly more aggressive, threatening the existing balance of power in South-East Europe. Romania tried to block the Bulgarian nationalism by promoting a policy of status quo, within which the political and diplomatic collaboration with the Central Powers and the Ottoman Empire was the key element. This paper analyzes - based on an unpublished archive material from the Romanian Archives - the Balkan dimension of the Romanian diplomacy and security politics at the late XIX and early XX century. [ABSTRACT FROM AUTHOR]