This chapter provides a comprehensive examination of how hostility towards Abu Hanifa evolved over three centuries among the proto-Sunni traditionalist network. It argues that the construction of heresy and orthodoxy depended on the circulation of discourses of heresy among textual communities. Transregional proto-Sunni traditionalists developed informal ways to regulate, discipline, and shape conceptions of orthodoxy and heresy. The chapter brings into sharp focus the key agents of proto-Sunni traditionalist orthodoxy: its texts, scholars, and figures who articulated and promulgated discourses of heresy. We can now discern a mature and virulent discourse of heresy among an influential network of proto-Sunni traditionalists seeking to malign, exclude, and marginalise Abu Hanifa and his followers from the proto-Sunni traditionalist conception of orthodoxy. In the tenth century, however, we can observe some attempts by proto-Sunni traditionalists to depart from the network’s emerging consensus and adopt a more accommodating tone towards Abu Hanifa and his followers, which marks the beginning of a broader conception of Sunni orthodoxy.