Imam Jafar-as-Sadiq the 6th Holy Imam of the Shi'ites was the Founder of the First Grand Islamic University. Imam Sadiq strengthened the foundations of Islamic Jurisprudence and he is also considered as "The Founder of the Imamia School of Jurisprudence".
Mansur Dawaniqi, the Abbasid caliph martyred Imam Sadiq through poisoning on 25th Shawwal 148 A.H. and his holy body was laid to rest in the Jannat-al-Baqi cemetery in the holy city of Madinah.
The Upright Upbringing
Ahlul Bayt News Agency - Imam Jaafar Al-Sadiq (peace be upon him) lived with his grandfather, Ali the son of Hussein (peace be upon them) for 12 years, and another 19 years with his father. The duration of his Imamate and succession after his father was 34 years.
The Political Circumstances during the Time of Imam Jaafar Al-Sadiq (peace be upon him)
Imam Jaafar Al-Sadiq (peace be upon him) became the Imam in a time of political turmoil. The clash between the Umayyads and Abbasids was at its height amidst different revolutions which were launched by the descendants of Imam Ali (peace be upon him), the followers of Zayd, and the Qaramites. There was also a slave revolution. This gave the Imam the opportunity to undertake activities of reform and religious enlightenment. The political conditions were suitable for such an undertaking, there was no rule of persecution and terror, and there were no causes for fear or to be careful of rulers. There was a fruitful scientific atmosphere marked by freedom of thought and belief.
Imam Jaafar Al-Sadiq (peace be upon him) kept away from movements opposing to the authority- especially those whose aims and tendencies did not represent Islam but merely intended to gain power.
Such a phase required a reformist revolution of a different type to confront the misconceptions which would have eradicated the true teachings of Islam if Imam Jaafar Al-Sadiq (peace be upon him) had become engaged in a military revolt instead. This is why we find that the Imam concentrated his efforts on strengthening intellectual principles in addition to assuming his role as an Infallible Imam of the Household (peace be upon them).
The Role of Imam Jaafar Al-Sadiq (peace be upon him)
The aforementioned political circumstances provided the Imam (peace be upon him) with a space of freedom. He was able to undertake a wide enterprise which was the foundation of a righteous community which bore the true teachings of Islam. Imam Jaafar Al-Sadiq (peace be upon him) followed certain measures:
1-The Confrontation of Devious Factions: During the era of Imam Al-Sadiq (peace be upon him), many deviant factions which were far from the teachings of Islam became famous. Thus, the Imam (peace be upon him) confronted these groups with different methods and tactics.
a-Heretics: The Imam (peace be upon him) faced heretics such as Ibn Al-Mukafa’, Ibn Abil ‘Awjaa, and Adisani in a calm and composed way. He invalidated their argumentations, refuted their ideas, and gained their trust and respect.
b-The inventors of false narrations: The Imam (peace be upon him) warned of their dangerous role which was the distortion of Islam. He stressed the necessity of rejecting narrations which did not conform to the Holy Quran and the Sunnah.
2-The Seminary of Science and Jurisprudence: The Imam (peace be upon him) proceeded in the footsteps of his father in the continuation of a seminary of jurisprudence and science which depended on the laws of Islam. The number of students increased to the extent that Hassan son of Ali Al-Washa’ said: “I found in this mosque (the Mosque of Kufa) nine hundred scholars each one of them saying: Jaafar son of Muhammad related [narrations] to me.” The scholars of narrations – in spite of the difference in their viewpoints - counted four thousand trusted transmitters of narrations who transmitted from Imam Al-Sadiq (peace be upon him).
This seminary gained even more significance because it included other than Shiites. This paved the way for spreading true Islamic teachings and lessening the distortion which had affected Islam due to the oppression of the Prophet's Household (peace be upon them).
The seminary of Imam Al-Sadiq (peace be upon him) also taught different fields of knowledge such as philosophy, doctrine, medicine, mathematics, and chemistry. In addition to this, this seminary established principles and sources for the deduction of laws of jurisprudence in order to ensure the continuity of Islamic legislation.
3-The Formation of a Righteous Shiite Community: The Imam (peace be upon him) seized the opportunity of the preoccupation of the Caliphate with wars and problems. He became immersed in the accomplishment of the main aim which was the formation of a righteous community which believed in the intellectual principles of the Prophet's Household (peace be upon them). He achieved this through teaching this group knowledge and piety and providing it with political awareness.
Imam Jaafar Al-Sadiq (peace be upon him) continued in strengthening the principles and aims of Imam Hussein's (peace be upon him) revolution. He performed this through urging people to visit the shrine of Imam Hussein (peace be upon him), establishing assemblies of mourning for him, and by informing people about the his revolution.
Imam Jaafar As-Sadiq (peace be upon him) amidst Two Phases
Imam Jaafar Al-Sadiq (peace be upon him) witnessed the demise of the Umayyad state and the rise of the Abbasid caliphate. It is usual that during shifts of power, people engage in wars and revolutions and rulers become engrossed with eliminating one another. This gave the Imam (peace be upon him) the opportunity to perfectly fulfill his scholarly and educational role. He kept away from political and military confrontations to occupy himself entirely with the most important deed upon which the establishment of Islam depended. He faced extraneous misconceptions and deviant groups. He was able to provide Shiite thought with propulsion which made it steadfast in the face of different schools of thought and which enabled it to remain to this very day. This is why the Shiite sect in reference to jurisprudence is named the “Jaafari sect”.
Imam Jaafar As-Sadiq (peace be upon him) and the Abbasid Caliph, Al-Mansur
The Abbasid Caliph, Al-Mansur, was furious of the great affection of people for Imam Al-Sadiq (peace be upon him) and their rallying around him. He expressed this fear a number of times and considered the Imam as: “the lump in the throat”. Al-Mufaddal son of ‘Amro related the situation, saying: “Al-Mansur wanted to kill Abu Abdullah Al-Sadiq (peace be upon him) more than once. Whenever he sent someone to kill the Imam, this person would become in awe of him when seeing him and would not kill him. However, he prevented people from going to the Imam and prevented the Imam from sitting with people. He kept full surveillance over the Imam.”
Al-Mansur feared harming the Imam because it would lead to great complications. However, this did not prevent him from intensely pressuring the Imam and placing him under full surveillance. This led Imam Al-Sadiq (peace be upon him) to advise his companions to adhere to secrecy and concealment.
Even though Imam Al-Sadiq (peace be upon him) was reserved, but Al-Mansur nonetheless committed a terrible crime when he poisoned the Imam who was martyred due to the consumption of that poison in the year 148 of Hegira. He was buried next to his father and grandfather in the graveyard of Al-Baqi’.
 Al-Mufid, The Guidance, volume 2, 179
 Al-Majlisi, The Seas of Light, volume 47, 180