This episode we trace the emergence of orthodoxy in Islamic thought. Starting with the debates about predestination and the nature of the Qu'ran we mark the development of Islamic theology from the writings of Hasan i Basri and the Qadarites or Qadiriyyah to the formation of the ahl al-Hadith and Mutazila movements. We discuss the influence of translation projects and Greek philosophy in the development of kalam or Islamic theology. We explore the contributions of Al Kindi and the the influence of the Abbasid civil war in shaping the minha of Al Ma'mun. We conclude with a discussion of the Ash'ari and the coalescing of Sunni orthodoxy and Shariah.