The papacy is commonly referred to as the world's oldest surviving institution and its capacity for survival and residual strength have long fascinated historians. This Cambridge History explores how and why the papacy has endured across the centuries. It examines its role as an instrument of authority, governance, and social and cultural influence, even as many other powerful institutions, empires, and states have disappeared or been reduced to largely ceremonial functions. Topics discussed include the papacy's relationship to secular power, including global events and political movements throughout history; its place in the governance of the Catholic Church, including its own internal structures and relationship with the Catholic hierarchy; and its entanglement in histories of art, culture, spirituality, gender, sexuality, bioethics, the environment, fashion, science, medicine, and the body. Providing new insights into how successive popes have interpreted the role of the papacy, this Cambridge History also reveals how that papal power has been contested in each historical period.