<p>The article assumes that collective ontological security is a main precondition for creating and fostering societal cohesion, particular in conflicting minority-majority constellations. It aims to discuss and contribute to the understanding of ontological security in historical perspective, particularly in relation to the emergence and endurance of ethnic conflicts over the long term. Reading national conflicts as an outcome of securitization and a consequence of striving for long-lasting ontological security, we can better explain the long-lasting effects of such conflicts. Such a perspective in analysis provides us with insights as to why nationalism has been so successful and has continued to trigger national strife. The article takes into consideration Polish-Ukrainian relations in the “long” nineteenth century, which escalated violently before World War I which are analyzed at the crossroads of urban and historical security studies in multi-ethnic societies and on research on memory cultures and political myths.</p>