This work is a critical study of the historical development of Christian doctrine, focusing especially on the period of the early church, and an assessment of the functions of doctrine. It challenges and corrects some of the theories of doctrine set out in George Lindbeck’s still-influential Nature of Doctrine (1984), particularly its ‘cognitive-linguistic’ model of doctrine, and offers a richer and more reliable account of the nature and functions of doctrine based on a close reading of the Christian tradition. This study notes the important parallels between the development of Christian doctrine on the one hand, and scientific theories on the other, using this to correct the influential account of the relation of heresy and orthodoxy developed by Walter Bauer. In place of Bauer’s account of the suppression of early orthodoxies, this study argues that multiple doctrinal formulations were proposed for discussion, only becoming ‘orthodox’ as a result of a consensual assessment within the church. The work also explores the way in which Christian doctrines can be seen as both ontological disclosures and epistemic frameworks, affirming the coherence of Christian doctrine.