Revanchism (from French: revanche, "revenge") is the political manifestation of the will to reverse territorial losses incurred by a country, often following a war or social movement. As a term, revanchism originated in 1870s France in the aftermath of the Franco-Prussian War among nationalists who wanted to avenge the French defeat and reclaim the lost territories of Alsace-Lorraine.
Revanchism draws its strength from patriotic and retributionist thought and is often motivated by economic or geo-political factors. Extreme revanchist ideologues often represent a hawkish stance, suggesting that their desired objectives can be achieved through the positive outcome of another war. It is linked with irredentism, the conception that a part of the cultural and ethnic nation remains "unredeemed" outside the borders of its appropriate nation-state. Revanchist politics often rely on the identification of a nation with a nation-state, often mobilizing deep-rooted sentiments of ethnic nationalism, claiming territories outside the state where members of the ethnic group live, while using heavy-handed nationalism to mobilize support for these aims. Revanchist justifications are often presented as based on ancient or even autochthonous occupation of a territory since "time immemorial", an assertion that is usually inextricably involved in revanchism and irredentism, justifying them in the eyes of their proponents.
The instance of revanchism that gave these groundswells of opinion their modern name came in the 1870s. French Revanchism was a deep sense of bitterness, hatred and demand for revenge against Germany, especially because of the loss of Alsace and Lorraine following defeat in the Franco-Prussian War. Paintings that emphasized the humiliation of the defeat came in high demand, such as those by Alphonse de Neuville.