While freely trespassing artificial boundary lines between disciplines, historians and social scientists continued to respect equally artificial borders between individual societies. Since the nineteenth century, for example, professional historians have viewed the past almost exclusively through the optic of a world divided into national states. They have treated history as a property attaching to national communities, presenting it as French history, Chinese history, Mexican history, and the like. They have taken cultural distinctiveness, exclusive identities, local knowledge, and the experiences of individual societies as the principal concerns of their studies. When dealing with eras before the emergence of modern national states, historians have generally studied the development of ostensibly coherent societies such as “imperial China” or “medieval Germany,” thereby construing the past through the lenses of a world divided into national communities.1 While addressing themes quite different from those of traditional political and diplomatic history, social historians and feminist scholars have also cast their studies within the framework of national communities. The metanarratives informing labor history and feminist history clearly suggest that class and gender are portable constructs of near-universal significance, but historians have rarely explored issues of class or gender in contexts larger than national states.2 Even when they have issued scorching critiques of patriotic narratives, historians have assumed that national states are the natural units of historical analysis.3 Indeed, in many ways, professional historical scholarship since the nineteenth century has been an artifact of the national-state era of world history.