The fourth century was a major religious battleground. The rise of Christianity, and in particular its dominance from Constantine onwards, marked an important shift in the religious history of the Mediterranean. Christianity saw this change as the victory of its monotheism over the polytheism of paganism. This volume studies how similarities between paganism and Christianity were obscured in the polemic that was waged by Christianity against paganism and in the pagan responses to it. The volume includes papers on Porphyry, Augustine, Themistius, Latin verse inscriptions, as well as dealing with the different ways in which Christian and pagan thinkers conceived of monotheism. A recurring theme in the papers shows that a concrete religious issue lay at the heart of such polemic: who can one worship? Christians would restrict worship to their God, whereas pagans accepted cultic acts for the many traditional deities. The debate about monotheism was therefore not just about conceptions of the divine, but was part of the creation and defence of social, cultural and religious identities in Late Antiquity. In exploring how the notion of monotheism was shaped by Late Antique polemic and how this still influences our understanding of it, this volume also hopes to inform contemporary debates about the dangers of monotheism.