Al-Wathiq

'''Abū Jaʿfar Hārūn ibn Muḥammad al-Wathiq bi'Llah (; 18 April 81210 August 847), commonly known by his regnal name al-Wathiq bi'Llah''' (), was an Abbasid caliph who reigned from 842 until his death in 847.

Al-Wathiq is described in the sources as well-educated, intellectually curious, but also a poet, who enjoyed the company of poets and musicians as well as scholars. His brief reign was one of continuity with the policies of his father, al-Mu'tasim (), as power continued to rest in the hands of the same officials whom al-Mu'tasim had appointed. The chief events of the reign were the suppression of revolts: Bedouin rebellions occurred in Syria in 842, the Hejaz in 845, and the Yamama in 846, Armenia had to be pacified over several years, and above all, an abortive uprising took place in Baghdad itself in 846, under Ahmad ibn Nasr al-Khuza'i. The latter was linked to al-Wathiq's continued support for the doctrine of Mu'tazilism, and his reactivation of the to root out opponents. In foreign affairs, the perennial conflict with the Byzantine Empire continued, and the Abbasids even scored a significant victory at Mauropotamos, but after a prisoner exchange in 845, warfare ceased for several years.