Mamoun died in 218 Hijri (833 AD). Mamoun was succeeded by his brother Mu'taman, the second heir-apparent after Imam Ali Al-Reza (AS). He came to be known as Al-Mu'tasim billah Abbasi. His niece Umme Fadhl now began to write to him complaining more than she did during the reign of her father because Mamoun always rejected her complaints. But Mu'tasim was jealous of Imam Ali Al-Reza (AS) from the very beginning. He had also opposed the marriage of Umme Fadhl to Imam Muhammad Taqi (AS).
Al- Mu'tasim now got a chance to settle his differences in this matter. Imam Muhammad Taqi's (AS) fame as a great scholar and the constant gathering of people around him as well as the fame of his world renown noble character annoyed him. The failure of the political tactics too, intensified his resentment. All these factors irritated him into enmity. In the second year of his reign he summoned the Imam from Madina to Baghdad, ordering his Governor in Madina expressly about it. Imam was compelled to set out for Baghdad leaving his son Ali ibn Muhammad (Naqi) with his mother in Madina.
For one year after the Imams's arrival in Baghdad, Mu'tasim did not do anything. He was hoping that the Imam would conform to the Royal ways of living and then this would be a source of infamy for the Ahlulbayt. But when he realised that the man was becoming more popular in Baghdad with his scholarly discourses with the scholars there, he had to act to stop this as all his ancestors did before him and use the silent weapon of poison to eliminate that thorn in his heart. The Imam died of poison on the 29th of Dhul Qa'ad 220 Hijiri (24.11.835 AD). He was buried by the side of his grandfather Imam Musa ibn Ja'far [a]. It is because of the two Imam's who were famous for their suppression of anger that the land was called Kadhemain, the two Kadhims, the enduring ones.
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