High Quality Content by WIKIPEDIA articles! Yugoslavism refers to nationalism or patriotism centred upon the Yugoslav ("South Slav") peoples within the Yugoslav populated territories of Southeastern Europe. Yugoslavism has historically advocated the union of all Yugoslav populated territories now composing Bosnia and Herzegovina, Bulgaria, Croatia, Montenegro, Serbia and the presently disputed region of Kosovo, Slovenia, and Vardar Macedonia. Yugoslavism was a potent political force during World War I with the assassination of Austrian Archduke Franz Ferdinand by Gavrilo Princip and the subsequent invasion of Serbia by Austria-Hungary, which sought to rally Yugoslavs against Austro-Hungarian imperial domination and in support of an independent Yugoslavia that was achieved in 1918.