In order to understand why the generally peaceful and non-expansionist leadership of Austria-Hungary regarded the relatively small Kingdom of Serbia as such an existential threat to its continued existence that it would risk a general European war to extinguish it, one must first understand the mentalities of the political class of the Habsburg Monarchy. The world-view that pervaded the literate and educated population of the Monarchy was based on the idea of the inseparability of language and nationality, and of the primacy of the nation-state in the political realm. The intellectual connections between language and the nation provided by the Enlightenment and Romantic philosophers were taken up by the dominant Liberal establishment in the 19th century, and given historical support by a number of national historians. These historical interpretations led to a sense of urgency to solve the ethno-linguistic anomalies of the Monarchy. The failure to solve these internal problems led to the search for an external solution, and ultimately to war with Serbia.