As early as in the second half of the fourth century, Gregory of Nazianzus assured his audience that the saints, living or dead, had the power to predict the future. This chapter seeks to explain how such predictions were obtained. There were at least three divinatory practices in which relics could be used: incubation in martyrs’ sanctuaries, interrogation of demoniacs in the presence of relics, and the drawing of lots on martyrs’ tombs. The problem is that the literary evidence for the first practice in the early period is rather scarce, for the second, exceedingly scanty, while for the third it is simply non-existent (we only know about it from material evidence). This reticence of the written sources does not necessarily reflect the actual popularity of these methods and plausibly results from their ambiguous character—neither praised nor condemned, they have left very few traces in literature.