Ja'far ibn Abdallah al-Mansur () was the elder son of second Abbasid caliph al-Mansur and elder brother of third Abbasid caliph al-Mahdi. As the elder son of al-Mansur, he was the candidate to the caliphal throne until his premature death.
Life Ja'far was the son of Abdallah ibn Muhammad al-Abbasi al-Hashimi (the future caliph al-Mansur) in 742/743. When Ja'far was eleven or twelve year old, his father became caliph.
His mother was Arwa. She was al-Mansur's first wife. Arwa also known as Umm Musa, whose lineage went back to the kings of Himyar. Her father was Mansur al-Himyari. She had a brother named Yazid.
Arwa had two sons, Muhammad (future Caliph al-Mahdi) and Ja'far. She died in 764. The two sons of Arwa, Ja'far and Muhammad were regarded as his heirs after the removal of Isa ibn Musa as heir. However, Ja'far died during his father al-Mansur's reign. His brother, Muhammad became sole candidate to the throne.
One of his al-Mansur's concubines was a Kurdish woman. She was the mother of al-Mansur's son Ja'far. Al-Mansur named this son after his elder son.
After Ja'far's death, his father took care of his young children. When his father, al-Mansur died. His brother caliph al-Mahdi took responsibility for his children. Al-Mahdi married his son and heir to Ja'far's daughter Zubaidah.
Relatives Ja'far was related to several powerful figures of Abbasid House. He was the older brother of al-Mahdi and he was also maternal grandfather of al-Amin.
Jafar also had several half-siblings, After his mother's death, his father remarried and had children from his wives.
No.AbbasidsRelation1 Al-Saffah Uncle2 Al-Mansur Father3 Al-Mahdi Brother4 Musa al-Hadi Nephew5 Harun al-Rashid Nephew (Son-in-law)6 Al-Amin Maternal-grandson7 Zubaidah Daughter8 Sulayman Half-brother 9 Isa ibn al-Mansur Half-brother10 Ya'qub Half-brother11 Jafar ibn al-Mansur Half-brother12 Salih al-Miskin Half-brother13 Qasim Half-brother14 Aliyah Half-sister The genealogy of the Abbasids including their rival Zaydi imams Caliphs of the Abbasid Caliphate Caliphs of Cairo Zaydi imams
References
Sources Abbott, Nabia (1946). Two Queens of Baghdad: Mother and Wife of Hārūn Al Rashīd. University of Chicago Press al-Tabari; Hugh Kennedy (1990). The History of al-Tabari Vol. 29: Al-Mansur and al-Mahdi A.D. 763-786/A.H. 146–169. SUNY series in Near Eastern Studies. State University of New York Press. pp. 148–49.