In order to recast scholarly understanding of scientific cosmopolitanism during the French Revolution, this essay examines the stories of the natural-history collections of the Dutch Stadholder and the French naturalist Labillardière that were seized as war booty. The essay contextualizes French and British savants' responses to the seized collections within their respective understandings of the relationship between science and state and of the property rights associated with scientific collections, and definitions of war booty that antedated modern transnational legal conventions. The essay argues that the French and British savants' responses to seized natural-history collections demonstrate no universal approach to their treatment. Nonetheless, it contends that the French and British approaches to these collections reveal the emergence in the 1790s of new forms of scientific nationalism that purported to be cosmopolitan -French scientific universalism and British liberal scientific improvement.In June 1796, Royal Society president Joseph Banks wrote to the French naturalist Jacques-Julien Houtou de Labillardière chronicling his efforts to convince the British foreign secretary to return the twice-seized natural-history collection that Labillardière claimed as his personal property. Despite Britain's seizure of the collection as a prize of war, Banks reassured Labillardière of his efforts to return the entire collection assembled by Labillardière and his naturalist colleagues during the d'Entrecasteaux voyage to the Pacific. Banks's promise was remarkable given competing property claims to the collection and the prior gifting of the plant specimens to Britain's Queen Charlotte, and above all because Europe's leading scientific and political powers were at war. Banks employed the cosmopolitan rhetoric of the eighteenth-century scientific Republic of Letters, stating to Labillardière,
