Answer
Al-Mu'tasim ruled as caliph for nine years, from 833 to 842 CE. His reign was marked by military expansion, particularly in Anatolia and Armenia, and by the construction of the city of Samarra as the new capital of the Abbasid Caliphate. Al-Mu'tasim was also known for his patronage of the arts and sciences, and for his harsh treatment of religious minorities.