Ja'far b. Muhammad b. Ali b. Husayn (702-765 AD, 83-148 AH), surnamed as-Sadiq (the truthful), is recognised as one of the most outstanding scholars of his time. His most recognised contribution is the many traditions of the Prophet that he narrated.
His life saw a period of major change in the Islamic world. His uncle Zaid and later Zaid's son Yahya revolted against the Ummayads but Ja'far seeing the fruitlessness of this task did not join them. Both Zaid and Yahya were martyred. The Ummayad dynasty finally faced a successful revolt and the Abbasids had gained the upper hand. However the suffering and oppression against Ja'far and his relatives worsened.
Ja'far established a theological school in Madinah attended by more than 4,000 students. Among those who benefited from Ja'far's knowledge were the Sunni Imams Abu Hanifa and Malik b. Anas. A less well-known fact is that Jabir b. Hayyan (the famous scientist known in the West as Geber) was a student of as-Sadiq.
There is no group that reveres Imam Ja'far as-Sadiq as much as the Shi'a who regard him as their sixth Imam. Ja'far was a descendant of the Prophet Muhammad (through his daughter Fatima) and of the first Shi'a Imam, Ali b. Abu Talib. It is due to Ja'far that the bulk of the Shi'a are commonly referred to as the "Jafaris".
Ja'far's immense influence on Islamic and scientific thought will perhaps never be quantified. Ja'far as-Sadiq died at the age of sixty-five and was buried alongside his great grand-uncle al-Hasan at the famous al-Baqi cemetery in Madinah.
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