This article examines the manuscripts into which compilers bound Dominican letters of spiritual direction in fifteenth-century Italy. It argues that manuscript compilers sought to model Observant Dominican sanctity after Jerome's late antique practice of writing letters of spiritual direction to women. The paper aims to contribute to the growing conversation around the development and spread of an Observant Dominican identity by demonstrating that compilers modeled Observant beati after Jerome's authoritative persona in order to argue for the ancient precedent of the reformers’ often controversial agendas, chief among them their active ministry to women.