The rise of European nationalism in the 19th century brought with it a glut of changes that would permanently alter the course of history. Rising nationalism in one country would spark greater nationalism in another, which would, in turn, motivate even greater nationalism in the first, gradually intensifying the cycle that would ultimately end in world war. Nationalism as an ideology engendered international competition that inspired absolute allegiance to an individual's nation-state. The ideology was fueled by industrial trade and imperialist developments that led nation-states to compete with rival nations. The powerful and intense impact of nationalism on individuals is demonstrated in Rudolf von Ihering's Two Letters (1866). By providing individuals with a group that they could be a part of, it became something that seemed to have unlimited potential for prosperity and it gave individuals a sense of empowerment. Initially, Von Ihering had vigorously opposed the Realpolitik policies implemented by Otto von Bismarck, declaring that "everyone [in Germany]...