Abdullah al-Aftah ibnJa'far al-Sadiq was the eldest surviving son of Ja'far al-Sadiq and the full-brother of Isma'il ibn Jafar. Abdullah’s title "al-Aftah" derives from the Arabic words "aftah al-ra’s" or "aftah al-rijlayn" used to describe his appearance.
Life
During the lifetime of his father, Abdullah al-Aftah had supported the revolt of his relative Muhammad ibn Abdallah An-Nafs Az-Zakiyya. Following Ja'far al-Sadiq’s death, the majority of Ja'far’s followers accepted Abdullah al-Aftah as their new Imam. These followers were known as the Fathites and, according to the Mu'tazili heresiographer Abul-Qasim al-Balkhi al-Ka‘bi, they were the biggest and most important section of the followers of Ja'far al-Sadiq. To support his claims, Abdullah al-Aftah seems to have claimed a 2nd Nass from his father and his adherents cited a supposed Hadith from Ja'far al-Sadiq to the effect that the Imamate must be transmitted through the eldest son of the Imam. However, when Abdullah al-Aftah died childless about 70 days after the death of his father, the bulk of his supporters went over to his brother Musa al-Kadhim. Other Fathites considered Abdullah al-Aftah the 7th Imam and Musa al-Kadhim the 8th Imam, while others believed the Imamate came to an end when Abdullah al-Aftah died. Another group invented a son for Abdullah al-Aftah, called Muhammad ibn Abdullah al-Aftah, because they unconditionally believed the Imamate could only be inherited from father to son, rather than from brother to brother. This group also claimed that Muhammad ibn Abdullah al-Aftah was the promisedMahdi. As the family continued to grow, an original family tree of the Prophet Muhammad from Imam Jaf’ar as Sadiq to his elder son Abdullah al Aftah is given below. This extensive family tree now extend to the 31stgeneration, and more than 100 surviving families throughout most continents.
Sāhib al-Haqq
In a letter sent to the Ismāʿīlī community in Yemen by Abdullah al-Mahdi Billah, which was reproduced by Ja'far bin Mansūr al-Yemen, ʿAbd Allāh al-Aftah ibn Jaʿfar al-Sadiq was referred as Sāhib al-Haqq or the legitimate successor of Imām Jaʿfar al-Sadiq by AbdAllāh in an attempt to explain the genealogy of his ancestors. Instead of tracing his descent to Ismā‘il b. Jaʿfar and his son Muhammad b. Ismāʿīl, the first Fatimid Caliph Abdullah al-Mahdi Billah designates Jaʿfar's eldest son ʿAbd Allāh as his forefather. According to ʿAbdallah al-Mahdi Billah, ʿAbd Allāh ibn Ja'far had called himself Ismāʿīl ibn Jaʿfar for the sake of taqiyya, and each of his successors had assumed the name Muhammad. ʿAbdallah al-Mahdi Billah explains the genealogy of the Fatimid Caliphs and he claims Fatimid ancestry by declaring himself to be ʿAli ibn al-Ḥusayn ibn Aḥmad ibn ʿAbadullāh ibn ʿAbd Allāh ibn Jaʿfar al-Sadiq. But the Imamah was later formulated in a different manner since ʿAbdallah al-Mahdi Billah's explanation of his ancestry was not accepted by his successors.
