The defeat of the Qarmatian state saw the gradual wane of their revolutionary brand of Ismaili Islam. Instead, under a process encouraged by Sunni rulers over the next four hundred years, Twelver Shia Islam became entrenched. According to historian Juan Cole, Sunnis favoured the quietist Twelver branch of Shi'ism over the Qarmatians and promoted its development in Bahrain. In the 13th Century, there arose what was termed the 'Bahrain School', which integrated themes of philosophy and mysticism into orthodox Twelver practise. The school produced theologians such as Sheikh Kamal al-Din Ibn Sa’adah al Bahrani (d. 1242), Sheikh Jamal al-Din ‘Ali ---