Muhammad al-Taqī or Muhammad al-Jawād (Arabic: الإمام محمد التقي الجواد) (Rajab 10, 195 AH - Dhu al-Qi'dah 29, 220 AH; approximately April 8, 811 AD - November 24, 835 AD) was the ninth of the Twelve Imams. His given name was Muhammad ibn ‘Alī ibn Mūsā, and among his titles, al-Taqī and al-Jawād are the most renowned. Muhammad al-Taqī was the shortest-lived of the Twelve Imāms, dying at the age of 25.
Birth and family life
He was born on the tenth of Rajab, 195 AH. His mother was Khaizaran, a woman from the family of Maria al-Qibtiyya.
Hakima, the sister of Ali ar Rida, is reported saying that on the night of al-Taqi’s birth her brother advised her to be present beside his wife. According to legend, al-Taqi at his birth looked at the sky and uttered confirmation of the oneness of Allah and the prophethood of Muhammad.
He undertook the responsibility of Imamate at the age of eight years.
He was a child when his father was killed. By reports, he did not act upon childish or whimsical impulses and he accepted adult responsibility and behaviours at an early age. Shi'a writers have propagated claims about his possession of extraordinary knowledge at a young age by likening his circumstances to that of the Islamic tradition of Jesus - a figure called to leadership and prophetic mission while still a child. 
According to Twelver Shi’ah Islam, the Imams are perfectly able to give judgment on all matters of religious law and their judgment is always legally correct. To that end al-Taqi supposedly receive a miraculous transfer of knowledge[weasel words] at the moment of the death of the previous Imam To that end it is reported, for example[weasel words] , that during his time in Baghdad he performed creditably in a public debate with one of the leading scholars of the city.
Marriage and lifestyle during Abbasid rule
After Al-Ma'mun had poisoned Ali al-Raza to death he endeavored to show that the death had come by a natural cause. Al-Ma'mun also brought al-Taqi from Medina to Baghdad with the plan of marrying him to his daughter, Umul Fazal. Although the Abbasids made strenuous attempts to forestall it, the marriage was duly solemnised.
After living in Baghdad for eight years, al-Taqi and Umul Fazal returned to Medina. There he found his relationship with his wife strained and upon the death of al-Ma'mun in 833 his fortunes deteriorated. The successor to his father-in-law was Al-Mu'tasim. With the new Abbasid ruler in power al-Taqi was no longer protected and his interests and position were imperilled by the dislike that al-Mu'tasim had for him.
In 835, al-Mu'tasim called al-Taqi back to Baghdad. The latter left his son Ali al-Hadi (the tenth Shi’ah Imam) with Somaneh (the mother of Ali al-Hadi) in Medina and set out for Baghdad. He resided there for one more year, becoming a well known scholar and popular in debates.
There are various accounts of the circumstances of his death.
Ibn Sheher Ashoob records  that Al-Mu'tasim encouraged Umul Fazal to murder him. She duly poisoned him to death on the twenty-ninth of Dhu al-Qi'dah, 220 Hijra (the 26th year after his birth).