This volume examines the process through which a historical character named al-Ḥasan al-Baṣrī was transformed into a myth by several groups in medieval Islam. Al-Ḥasan lived in the city of Basra, southern Iraq, and was famed for his piety, which attracted to him a large number of disciples who went on to play important roles in the formation of several religious trends. The literary corpus (sayings, stories and letters) ascribed to him has been used as a window into early Islamic religious and intellectual thought. But as this study shows, this corpus was largely forged in different periods, in some cases even a thousand years after al-Ḥasan's death. It tells us more about the beliefs of those who forged the sayings, stories and letters rather than about al-Ḥasan's thought and time.