After Napoleon ravaged Europe and was exiled to Elba Island, the leaders of Europe met at the Vienna Congress to determine the fate of the continent moving forward. Italy and Germany were divided and France lost key territory as a result of the Franco-Prussian War.
As the spirit of nationalism grew in Europe in the late 1800’s both Germany and Italy strove for re-unification under the banner of nationalism, and France used nationalist feelings to stir the people to regain their territory.
While the assassination of Archduke Franz Ferdinand “officially” started the war to many historians, the desire of the Slavic peoples to control their own destiny and align with Serbia rather than the Austro-Hungarian Empire was the catalyst of that action. Nationalism at its finest.
Beyond those countries, Europe as a whole used nationalism to call its people to action to assert their dominance and prove that they belonged at the head of the European table.