In classical Roman law, a private act such as child exposure, child sale, or the pledging of children could not change the legal status of a child or turn a freeborn into a slave. In practice, however, decisions concerning the status of foundlings lay with their finders, who could readily enslave them. In the fourth century CE, in an attempt to minimize child exposure, Constantine legalized this practice, granting finders the official power to decide the legal status of foundlings: whether a child would be raised as a slave or adopted and raised as a freeborn citizen. Jews and Christians living under Roman rule addressed this question using Roman legislation alongside their own legal thought, practices, and traditions. In this paper, I survey the Jewish and Christian approaches to child exposure and demonstrate how Roman legislation was transplanted into two new legal contexts. While the Palestinian rabbis cited the Constantinian legislation, they molded it in the form of conversion, because Palestinian rabbinic halakha did not acknowledge legal adoption of children. The Christian writers, by contrast, at first sight appear to have ignored the question of status. They focused on defining exposure as murder, comparable to abortion and infanticide. A closer look, however, reveals that they replaced the question of civil status with one of religious status, describing the adoption of a foundling as baptism and inclusion in the growing Christian community.