An expression of French nationalism, incorporating both elements of nineteenth-century nationalism, was written by Fustel de Coulanges in the early autumn of 1870. In the midst of the Franco-Prussian War, de Coulanges, a French historian teaching in Alsace at the University of Strasbourg, wrote an open letter to the German historian Theodor Mommsen explaining why the French-controlled province of Alsace should remain French and not become part of any new German state. Prussia defeated France, and despite de Coulange’s arguments, the two French provinces of Alsace and Lorraine were taken from France in 1871 and appended to a new, united Germany. In 1919, as part of the Treaty of Versailles, Alsace and Lorraine were returned to France. In many ways, the arguments of de Coulanges, though focused on two small provinces, exemplified the contentious spirit and emotional fervor of late-nineteenth-century European nationalism.
Alsace is a very odd place. It is a region in France which is largely inhabited by Germans and Prussians. Yet, it still was cultural hub for the French. Then, it was taken from France and became a German province. But today, it is a part of France still. The history of Alsace would be an interesting thing to research.