This study discusses the religious persecution against those not adhering to Mütazila doctrine carried out by the Abbasid caliph al-Mäm¿n and known as "mi¿na". It explores the previous sociological, theological and political sitiuation, the mi¿na's process and its effects afterwards on Sunni theology. An exploration on the impact the 9th century religious persecution known as "mi¿na" had on Islamic history and theology.