Krajina ("borderland"), the Habsburg Military Frontier, was once the name of a string of territories which provided an essential link in the chain defending Europe from the Ottoman onslaught in the 16th and 17th centuries. For many generations the Serbian population of these regions was periodically decimated by warfare in the service of the Austrian Emperor. In 1941-1945 the Serbs were subject to a genocidal attack after the Germans put the Croatian Ustaša movement in power in Zagreb. Their resistance to this slaughter and the ensuing epic struggle is the story both of the royalist Četniks and of their bitter rivals for post-war power, Communist-led Partisans. The history of the Krajina Serbs, ending in the mass exodus of 1995, is an element in the story of most of the great wars in Europe, from the Ottoman offensives after the fall of Constantinople to the last decade of the twentieth century.