the importance of local customs and traditions, to the movements that would redraw the map of Europe and lead to calls for self-determination of nationalities, nationalism was one of the key vehicles of Romanticism, its role, expression and meaning. One of the most important functions of medieval references in the 19th century was nationalist. Popular and epic poetry were its workhorses. This is visible in Germany and Ireland, where underlying Germanic or Celtic linguistic substrates dating from before the Romanization-Latinization were sought out. Early Romantic nationalism was strongly inspired by Rousseau, and by the ideas of Johann Gottfried von Herder, who in 1784 argued that the geography formed the natural economy of a people, and shaped their customs and society. The nature of nationalism changed dramatically, however, after the French Revolution with the rise of Napoleon, and the reactions in other nations. Napoleonic nationalism and republicanism were, at first, inspirational to movements in other nations: self-determination and a consciousness of national unity were held to be two of the reasons why France was able to defeat other countries in battle. But as the French Republic became Napoleon's Empire, Napoleon became not the inspiration for nationalism, but the object of its struggle. In Prussia, the development of spiritual renewal as a means to engage in the struggle against Napoleon was argued by, among others, Johann Gottlieb Fichte, a disciple of Kant. The word Volkstum, or nationality, was coined in German as part of this resistance to the now conquering emperor. Fichte expressed the unity of language and nation in his address "To the German Nation" in 1806: Those who speak the same language are joined to each other by a multitude of invisible bonds by nature herself, long before any human art begins; they understand each other and have the power of continuing to make themselves understood more and more clearly; they belong together and are by nature one and an inseparable whole. ...Only when each people, left to itself, develops and forms itself in accordance with its own peculiar quality, and only when in every people each individual develops himself in accordance with that common quality, as well as in accordance with his own peculiar quality—then, and then only, does the manifestation of divinity appear in its true mirror as it ought to be. This view of nationalism inspired the collection of folklore by such people as the Brothers Grimm,