jats:titleAbstract</jats:title> jats:pThe ideas of a human war on nature, and a human war on animals more specifically, are now current in international politics and international law. This article unearths a historical understanding of war on animals as one paradigm of human relations with animals in the early modern law of nature and of nations (16th to 18th centuries). It shows how jats:italicdominium</jats:italic> (property or mastery) over animals was placed at the origin of all human jats:italicdominium</jats:italic>, and was in consequence conceptually central to its legitimation. It also shows, however, that jats:italicdominium</jats:italic> over animals was not straightforward to justify, because, although they were not human beings, they were seen as sufficiently like human beings in sentience to resist being legally treated like plants or inanimate objects. This article tracks three successive paradigms, all of all of which involve conceptual tensions that are illuminating for current thinking concerning violence against animals.</jats:p>