The nation state received a philosophical underpinning in the era of Romanticism, at first as the "natural" expression of the individual peoples (romantic nationalism: see Johann Gottlieb Fichte's conception of the "Volk", later opposed by Ernest Renan). The increasing emphasis during the 19th century on the ethnic and racial origins of the nation, led to a redefinition of the nation state in these terms. Racism, which in Boulainvilliers's theories was inherently antipatriotic and antinationalist, joined itself with colonialist imperialism and "continental imperialism", most notably in pan-Germanic and pan-Slavic movements.