This chapter considers the implications of this study for the broader history of medieval Sunnism and comparative work on heresy and orthodoxy in the field of religious studies and history. It concludes that proto-Sunni orthodoxy was an evolving process. Not only did it undergo a number of iterations, but it was characterised by internal contradictions and divisions. The failures of proto-Sunnism were as relevant to the formation of medieval Sunnism as were its successes. Medieval Sunnism was a product of constant tensions. These required negotiations. In order to appreciate the historical achievement of classical Sunnism, examining its most contentious times is integral to making sense of its most agreeable times. In this sense, to study the formation of orthodoxy and heresy in medieval Islam is to come to terms with a truism that ‘traditions, when vital, embody continuities of conflict’.