He died, by poisoning mixed in his fruit by Mamoon.

His body was prepared for burial by his son the Imam Mohammad AI-Jawad(as) and he was buried in Meshad, Khorasan in Iran, where his shrine stands now.

It is needless to speak of his achievements in vast knowledge, virtue, nobility, generosity, moral perfections, humbleness and worship of Allah(swt).

Mamoon Al-Abbassi, then the Calipha asked him to take charge of the administration of the Muslim government but he did not accept it because he knew that things will not go the way he liked them to go.

It was just like the case of his great grandfather the Imam Ali Ibin Abe Taleb(as) who did not accept the post of leadership with the condition set by the counsel that he should run the government according to the book of Allah(swt), the traditions of The Holy Prophet(pbuh) and the policies of the two previous Caliphas Abu Bakir and Umar Al-Khattab.

Imam Ali(as) couldn't ofcourse and didn't accept such an offer but Uthman accepted it. Hence he was appointed the third Calipha, over Imam Ali(as)!

When the eighth Imam did not accept the post of the leadership of the Muslim govermnent, Mamoon then asked him to be his successor and the Imam accepted it with the condition that he will not be asked to take part in any governmental task during the life time of Mamoon.

Because quite simply, Mamoon's government policies were completely contary to Islam principles and the teachings of The Holy Prophet Mohammad(pbuh).

Some examples of his vast knowledge came to light when Mamoon invited the scholars of different schools of thought to attend a seminar of debate over the theological issues and matters of the doctrines of faith.

For his worship he would stay up for many nights and read the whole book of Holy Koran in just over three days. Very often he would fast and also pray a thousand prayers in twenty four hours.

He was very generous to everyone especially the poor. He would help the needy during the night so that no one would recognise him.

He never did any injustice to any one in words or deeds. He was not loud spoken but always spoke softly with a polite manner and was cordial with everyone. He always sat politely and never slouched in presence of others. He would call all the members of his family and servants to have dinner or lunch together.