The significance of captives in the history of empire has come to the fore in several recent books and articles. Linda Colley starts her intriguing study of this theme with the stories of two famous, if legendary, British captivesRobinson Crusoe and Gulliverexplaining how each represents a different conception of empire: the former a shipwrecked ex-slave turned conqueror and colonizer; the latter an overseas adventurer who is captured, humiliated, and terrorized but ultimately transformed by the values of his captors into a critic of his own society. Far from the heroes of Defoe and Swift, female captives featured in conversion accounts on the east Roman frontiers represent another response to captivity in a very different imperial worldthat of the Roman and Iranian empires of late antiquity. These protagonists neither came to dominate the kingdoms in which they were held nor assimilated the culture of their captors but maintained their identity, their customs, and their religion in captivity. Indeed, these captives went further still, actually transforming the peoples and governments under which they were held from their very positions of subordination.