Ash'aris are those who adhere to Imam Abu al-Hasan al-Ash'ari in his school of theology. Ashʿarism or Ashʿarī theology is one of the main Sunnī schools of Islamic theology, founded by the Arab Muslim scholar, Shāfiʿī jurist, and scholastic theologian Abū al-Ḥasan al-Ashʿarī in the 9th–10th century. It established an orthodox guideline based on scriptural authority, rationality.