This book explores the way in which three ancient historians, writing in Latin, embedded the gods into their accounts of the past. Although previous scholarship has generally portrayed these writers as somewhat dismissive of traditional Roman religion, it is argued here that Livy, Tacitus and Ammianus saw themselves as being very close to the centre of those traditions. The gods are presented as a potent historical force, and a close reading of the historians' texts easily bears out this conclusion. Their treatment of the gods is not limited to portraying the role and power of the divine in the unfolding of the past: equally prominent is the negotiation with the reader concerning what constituted a 'proper' religious system. Priests and other religious experts function as an index of the decline (or restoration) of Rome and each writer formulates a sophisticated position on the practical and social aspects of Roman religion.