al-Ash'ari

Abu al-Hasan Ali ibn Isma'il al-Ash'ari (c. 260/874 - 324/935-6) was a Muslim theologian born in Basra, in present-day Iraq, who became the namesake of one of the dominant schools of Sunni kalam (speculative or rational theology). Tradition holds that he descended from Abu Musa al-Ash'ari, a Companion of the Prophet Muhammad, though early sources establish little of his family with certainty, and even his birth year is reported variously as 260 or 270 AH.

As a young man he studied under Abu Ali al-Jubba'i, a leading teacher of the Mu'tazila, a theological movement that stressed reasoned argument and God's justice. Reports say that around his fortieth year al-Ash'ari publicly renounced Mu'tazili doctrine. Later biographers dramatize the break with a famous "three brothers" debate in which al-Jubba'i is left speechless; modern scholars regard this anecdote as a later literary story rather than documented history.

Settling in Baghdad, al-Ash'ari turned his training against his former school, arguing for positions associated with the people of hadith (such as God's real attributes and an uncreated Qur'an) but defending them with the rational tools of kalam. Whether this made him a restorer of orthodoxy or an innovator is itself a matter debated between schools, not a settled fact. He died in Baghdad around 324/935-6; the biographical tradition also records 330 and 333 AH, though 324 is the standard date. The school later built in his name, the Ash'ariyya, became, alongside the Maturidi school, a principal current of Sunni theology.