This volume engages with the centrality of the popes within the Catholic Church and the claim of papal authority as it was exercised through the institution's various governing instruments. Addressing the history of the papacy in the longue durée, it highlights developments and the differences between the first and second millennium of the papacy. The chapters bring nuance to older historiographical models of papal supremacy, focusing on how apostolic primacy was contested and re-negotiated, and how the contours of power relationships shifted between center and periphery. The volume draws attention to questions about papal supremacy across time, place, and transnational lines; the function of law in the exercise of papal authority; the governance of the church in the form of the Curia, synods, and regional and ecumenical councils; the governance of the Papal States; the management of finances and church-state relations; and the relationship between papal temporal and spiritual authority.