19th century proponents of German unification advocated considering the Little Belt (German: "Kleiner Belt") as the northern border of Germany, and the Belt is mentioned in this context in Ernst Mortiz Arndt's "Was ist des Deutschen Vaterland?" (1813) and the "Deutschlandlied" (1841), the third stanza of which is the current German national anthem. This reflects the fact that the Denmark-Germany border has shifted several times over the centuries, so that the current Danish region of Southern Jutland was once part of the Duchy of Schleswig.