This book studies early Byzantine hagiographic Lives of saints who disguise their identities (4th-10th cent.), including female saints who live as men in male monasteries, 'holy fools' who pretend madness to hide their sanctity, and 'beggar-saints' who keep their true identities hidden from their family while they live in or near their parental home. Focusing on the element these saints have in common, disguise, the book addresses a central paradox: late antique religious authorities fiercely condemned any form of roleplaying or pretence, yet these narratives portray saints engaged in exactly that. Using the tools of narratology, this study sheds light on the hagiographic narratives' complexities and nuances, thus revealing how they avoid portraying the saints in a negative light and how the saints' performances become a vehicle for specific messages. It argues that the Lives solicit reflection about issues related to human experience of physical reality, identity, and about the slipperiness of these concepts, while offering, at the same time, stable conceptualizations of religious truth.