Abstract
This article examines the historical roots of the One Health concept and highlights its deep convergence with Florence Nightingale's Environmental Theory. Although One Health gained prominence in the early 2000s, its intellectual foundations are much older, encompassing Indigenous knowledge systems, nineteenth-century public health, and the work of Virchow, Osler, and Schwabe. Through a historical-conceptual analysis of Nightingale's writings and key One Health milestones, the article shows how her emphasis on environmental determinants, stewardship of natural and built environments, systematic observation, statistical evidence, and coordinated cross-sectoral action anticipated core One Health principles. Five areas of convergence are identified: prevention focused on environmental determinants, environmental stewardship, data-informed decision making, transdisciplinary collaboration, and continuous system improvement. The article argues that Nightingale's legacy positions nursing as a strategic actor in the local implementation of One Health, particularly in designing therapeutic and healthy environments and integrating environmental indicators into care, governance, and health policy.