Al-Mu'tasim was the eighth caliph of the Abbasid Caliphate, ruling from 833 to 842 CE. He was known for his military campaigns and efforts to strengthen the caliphate's authority. Al-Mu'tasim established a new capital at Samarra, which became a center of culture and power during his reign. He is also recognized for his patronage of the arts and sciences, promoting scholars and artists. Al-Mu'tasim's reign marked a period of significant development in Islamic civilization, contributing to advancements in various fields, including philosophy, medicine, and architecture.