The historical-comparative method, starting as it did from its study of Sanskrit familiarities, was initially (between Sir William Jones and Franz Bopp) applied to the larger linguistic complex of the Indo-European languages. The method was applied to the Germanic language family by Jacob Grimm, who in formulating his famous “laws” described its position in terms of the shift from an older initial consonant k, p or t to h, f and th (cf. Latin canis, pater and tonitrus as opposed to English/German hound/Hund, father/Vater or thunder/Donner). A second consonant shift characterized, in Grimm’s model, the separate position of German within the larger Germanic complex: as the language that had morphed from pipe to Pfeife, and from tin to Zinn. This epoch-making systematization occasioned some terminological quarrels and uncertainties: Rask resisted the family name “Germanic” and preferred “Gothic”, and Grimm used Deutsch sometimes for the High German as spoken and written in the German lands (e.g. in his Deutsches Wörterbuch), sometimes for a larger cluster of languages including Dutch and Flemish as well as Frisian and Anglo-Saxon (e.g. in his Deutsche Grammatik and Geschichte der deutschen Sprache). Grimm and his followers (including his early collaborator Radlof) saw the Germans as an array of tribally-descended branches (linking back to the ancient Bavarians, Burgundians, Franks, Hessians, Saxons, etc.); this open-ended modular structure would allow for the inclusion of different populations as additional German(ic) Stämme: Swedish Goths, Danish Teutons and Cimbri, all with different dialects or language variants belonging together in a greater ethnic whole and with present-day German as the geographical and cultural centre of gravity.

As this semi-systematized taxonomy of a German language-cum-dialect family emerged, texts were coming to light which supported the idea of a common cultural descent and a wide European spread. Nordic saga material had obvious analogues in German legendary romance. The reach of the Saxons was traced overseas into England, and Beowulf was claimed by German scholars as a co-Germanic text; even Flanders, later in the century, developed an ethnic ancestry myth that saw the country’s population as descended from seafaring Saxons called “Kerels”. Grimm’s consonantal shifts explained the identity of the fabled Dietrich von Bern and the historical Theodoric of Verona; Angelo Mai’s discovery of Bible fragments in Gothic, in Theodoric’s northern Italy, sharpened awareness of that language as a documented repository of archaic Germanic and of the erstwhile dominion of Ostrogoths (and, later, Longobards) south of the Alps. (The tardy progress of Castiglione’s edition of these Gothic fragments was followed by German philologists like Grimm and Maßmann with great interest, impatience and some ethnic suspicion.) There was even some echo across the Atlantic Ocean, as some pro-German or Scandinavian groups in the US celebrated the memory of the medieval Icelandic seafarer Leif Erikson, who had purportedly made landfall in the New World, as a Germanic founding father.

A cultural and political sense of Pan-Germanic kinship, derived from these philological models, and expressed also in a fashion for the runic alphabet, was fluid and vague, and was only turned into a political agenda by certain elements within National Socialism, concentrated around Himmler’s SS and Ahnenerbe. At the higher level of aggregation, the Germanic category was easily conflated with a larger, vaguely-defined “Nordic” or “Aryan” race which comprised other Indo-European language communities as well (including Mediterraneans and northern or upper-caste Indians, but not, curiously, Slavs). At a lower level it boiled down to an inclusive German chauvinism, ultimately derived from Arndt, that stressed the collectivity of the constituent Stämme and raised irredentist German claims to outlying areas which in the days of the Great Migrations had been settled by one “German Stamm” or another: Holland, Flanders, Alsace-Lorraine, the German-speaking portions of Switzerland and Austria including South Tyrol, uncertainly-demarcated swathes of land between the Baltic seaports and Poznán/Posen, and even Jutland. Their “Germanic” cultural familiarity had been philologically argued by the likes of Arndt and Grimm; a political agenda, often with anti-Semitic and anti-Slavic overtones, took hold in the later decades of the 19th century, feeding into annexationism. The German appellation for this ideology was Alldeutsch or völkisch; the name “Pan-German” appears to have been used mainly by hostile French commentators, in an analogy calqued on Pan-Slavism.

Such annexationist Pan-Germanism in turn informed certain German war aims in both World Wars, and policies in the territories occupied during those years. In addition, Germanism seems to have been the informal driving power behind various manifestations of cross-national, political-cultural solidarity in diverse contexts. Scandinavism may be seen as a Nordic sub-type of Pan-Germanism (with, as far as Denmark was concerned, an anti-German defensive aspect). In mid-19th-century Britain, Saxonism stressed the continental-Germanic roots of the English nation, and fostered British-German ties on the basis of what was perceived as the two countries’ shared ethnicity and moral outlook (as conformed in Protestantism). As political relations between Britain and Germany soured after 1871, England’s Germanic ties were conveniently relocated to the Nordic world, by an interest in saga literature and Viking heritage as evinced by the likes of William Morris. In Flanders, the solidarity of Vormärz Romantics like Gustav Höfken and Hoffmann von Fallersleben invoked the Germanic nature of Flanders as a bulwark against encroaching Frenchness, a formula that remained fatally influential in the Flemish Movement well into the 20th century. Germanism also informs, within German cultural production, the great appeal of mythological topics (Nordic mythology being co-opted into a Germanic whole as a result of Grimm’s Deutsche Mythologie, and culminating in Wagner’s Ring cycle) and of the earliest, tribal period of German history (e.g. in the historical writings and history-novels of Felix Dahn).