This article draws comparatively from civil disputes over community authority in eighteenth-century Oaxaca, Mexico, as well as Lima and Trujillo, Peru, to spotlight a turning point within a longer history of the invocation and invention of indigenous legal custom. Early modern Spanish notions of legal custom had two temporal trajectories, one harkening back to a “time immemorial,” the other pointing to repeated community practice. In the late eighteenth century, indigenous litigants and legal officials added another temporal dimension to native custom. This version of custom contained elements we almost never associate with colonial indigenous lawsuits: immediacy, historicity, and precedent. These elements of custom place indigenous lawsuits within a broader unfolding of modern historical thought in the so-called West.