This article examines the early history of the Hospital de San Hipólito in Mexico City, which delivered charitable care and basic medical services to a vulnerable category of colonial subjects known as “pobres dementes,” or mad paupers. In spite of the vast and robust literature on the history of madness and its institutions, surprisingly little is known about this institution, which, founded in 1567, holds a claim to being the first hospital of the Americas to specialize in the care and custody of the mentally disturbed. The article draws on archival sources and biographies of the hospital's founder to reconstruct San Hipólito's origins, activities, patient population, and interior life. It asks how the hospital registered the transfer and adaptation of institutions, ideas, and practices from the Old World to the New. It argues, ultimately, that San Hipólito served as an imperfect tool of colonial governance—and that it did so less through exerting control over a multiracial, recalcitrant, and marginal group of colonial society than through the reproduction of charitable practices and ideas that lent legitimacy to Catholicism and Hapsburg models of paternal authority.