an Entity references as follows:
Abū al-ʿAbbās Aḥmad ibn Muḥammad ibn Muḥammad (Arabic: أبو العباس أحمد بن محمد بن محمد; 836 – 17 October 866), better known by his regnal title Al-Mustaʿīn (836 – 17 October 866) was the Abbasid caliph from 862 to 866, during the "Anarchy at Samarra". After the death of previous Caliph, Al-Muntasir (who had not appointed any successors), the Turkic military leaders held a council to select his successor. They were not willing to have Al-Mu'tazz or his brothers; so they elected Ahmad ibn Muhammad (أحمد بن محمد), a nephew of Al-Mutawakkil, who took the regnal name Al-Mustaʿīn bi-ʾllāh (المستعين بالله "he who looks for help to God").