The Spokesman of the Right of Imamate and the Arbor of Generosity Sinai, the Owner of Extended Servitude, the Resurrector of Religion’s Affairs, Imam Musa Bin Jafar Al Kazem. His glorified name Musa and respectable patronymic Abul Hassan, famed in books of history and traditions as Abul Hassan the first and his celebrated most famous title Al Kazem. The birth of his auspicious essence was on the 7th of Safar 128 Hijri (746 AD) at Abwa between Mecca and Medina; and during the martyrdom of his honorable father was 20 years old. His paragon exalted mother was an Omme Walad by the name of Hamidah Berberiyah or Andalusiyah. His magnanimous father His Holiness Sadiq (AS) for reasons of the situation of that time had not the necessary conditions to appoint true guardian and successor and Imam of the time openly and publicly; secretly to a few of his special disciples such as Fazl bin Omar and Abdulrahman bin Abi Hajjaj and a few others who were trustworthy and also to his other two sons, Ali bin Jafar and Ishaq bin Jafar, introduced His Holiness Musa Al Kazem as his successor and leader and Imam of the people. But as it was cited in the biography of His Holiness in his external and open will, he named five persons as his successors, one of them was Mansoor the caliph and the theosophy of this command was manifested at the time when Mansoor’s letter reached the governor of Medina after the martyrdom of His Holiness Sadiq (AS) to investigate if His Holiness Jafar bin Mohammad has appointed anyone as his successor, to summon that person and behead him, that through this pseudo-will the life of His Holiness Kazem was protected. In short, His Holiness Kazem (AS) in the year 148 Hijri (766 AD) when his honorable father was martyred sat on the throne of guardianship and engaged in guiding the worshippers, till the year 158 Hijri (772 AD) came Mansoor set out for Hajj and came out of Baghdad and in Baermeymon (a place in the vicinity of Mecca) became sick and surrendered his spirit to the one who takes away souls. His age was fifty three and the period of his caliphate was twenty two years.
After him, his son Mohammad bin Mansoor titled Mahdi sat on the seat of caliphate and in the year 160 Hijri (777 AD) for his son Musa titled Hadi took allegiance from the people. In the year 182 Hijri (798 AD) Hakam bin Hesham known as Al Muqanna emerged, claimed divinity and by means of jugglery for a period of two months every night would bring out a shining round disc from a well resembling the moon which would light up a far distant. And the caliph Madhi sent the army to conquer him; and when al Muqanna saw his defeat and captivity killed his kinfolks with poison and threw himself in a barrel of nitric acid to be dissolved. Mahdi in the year 166 Hijri (783 AD) took allegiance from the people for his second son Haroon as caliphate after Hadi and in the year 169 Hijri (786 AD) left for the hereafter and his son Musa titled Hadi sat on the seat of caliphate in his place. In this year His Excellency Hussain bin Ali bin Abedin from the descendants of His Holiness Hassan Mujtaba (AS) well known as Saheb Al-Fakh with 26 persons from the Alavians emerged in Medina and killed the superintendent of police of Medina and occupied the city of Medina. Meanwhile, a group from the Bani Abbas who had come to Medina with the intention of Hajj, started a carnage with His Excellency and martyred His Excellency with most of the companions who most of them were Alavians and only Yahya bin Abdullah al Mahz escaped safely from that conflict and ran off to the Deylam area and thereafter emerged during the time of Haroon. In short, Hadi during the time of his caliphate highly endeavored to make his brother Haroon resign and nominate his son Jafar as the successor; but Haroon was not deceived by wealth and riches and did not fear from promises and threats and by no means was willing to resign, even matters reached to a stage that Hadi intended to kill him, but death did not give him a chance so that he could fulfill his purpose. It is said when his mother became aware of Hadi’s intention to kill Haroon, at night with her slave women put a pillow on Hadi’s mouth and suffocated him. Anyway, Hadi after one year and three months of caliphate in the year 170 Hijri (787 AD) died and the next day after his death, the people renewed allegiance to Haroon with the diligence of Yahya bin Khaled Barmaki and placed him on the seat of caliphate and gave him the title of Al Rashid; and in the year 176 Hijri (793 AD) Yahya bin Abdullah al Mahz who had fled from the conflict of Fakh emerged in Deylam. Haroon Al Rashid wrote to Fazl bin Yahya Barmaki governor of Khorasan to give Yahya security and send him to Baghdad. Fazl gave security to Yahya and brought him to Baghdad with himself. Haroon treated Yahya with affection and leniency for a while, then with the backbiting of Abdullah bin Mosayyab bin Zabir imprisoned Yahya, and for two consecutive nights beat him so much with cane that he fell ill and died in prison.
In the year 182 Hijri (798 AD), Haroon took allegiance from the people for caliphate of his second son Abdullah Mamoon after his elder son Mohammad Amin. His Holiness Musa bin Jafar (AS) though would not interfere in any affairs except guiding mankind and did nothing else, nevertheless his enemies did not stop backbiting him with Haroon. As by the plot of some of his enemies and also innate malice, Ali bin Ismail bin Jafar Al Sadeq intended to travel to Baghdad for backbiting His Holiness. His Holiness Kazem when heard about his journey summoned him and said: son of my brother, where do you intend to go? Said: I am going to Baghdad. Said: What intention do you have by travelling to Baghdad? Said: I have a lot of debts and my life passes with difficulty. Said: I will pay your debts and will help you in your living sustenance and gave him advice and counseled him and prohibited him from the journey to Baghdad. Anyhow, the words and statements of His Holiness did not influence him and he said that he is compelled to go to Baghdad. Said: If you go, pay attention and take God into consideration that you don’t have your hands in my blood and in killing me and making my children orphans. Then he gave him some money. Nevertheless, when he reached Baghdad, he backbited His Holiness (AS) in such a way that Haroon in the same year under the pretense of Hajj went towards Medina and in Medina on the first night went to the Mosque of His Holiness Mohammad (S) and facing the sacred grave and – in his thinking – apologized that I am compelled to arrest Musa Kazem your son; and on the same night arrested His Holiness, and sent His Holiness to Basra handcuffed to Issa bin Jafar al Mansoor governor of Basra to imprison him.
His Holiness was imprisoned in Basra for one year. Then Haroon wrote to Issa to martyr His Holiness. He did not agree to this order, wrote back saying: during all the time of imprisonment of Musa bin Jafar I was attentive of him and, except worship of his God; I did not observe anything else from him. Therefore, I thus advise to release and free him, otherwise, send someone else so I will hand him over. Haroon sent an agent so that he could take charge of His Holiness from Issa and to take him to Baghdad and handed him over to Fazl bin Rabe’i and was in prison of Rabe’i for a while and Haroon after sometimes also ordered Fazl to martyr His Holiness. Fazl also refused, then handed His Holiness to Fazl bin Yahya Barmaki. Haroon ordered him to treat His Holiness with severity and harshness, but Fazl bin Yahya Barmaki as much as possible made available all means of comfort for His Holiness secretly. The spies informed Haroon who was in Raqqa at this time about Fazl’s gentle behavior towards His Holiness Musa ibn Jafar. Haroon sent his servant Mansoor to whip Fazl hundred lashes for his lenient behavior with His Holiness Musa and took His Holiness away from him and handed him over to Sandi bin Shahak. The accursed Sandi imprisoned His Holiness in a narrow and dark jail. Finally Haroon ordered Sandi (according to differences in narrations) to martyr His Holiness by means of poisonous food or poisonous dates. His Holiness after being poisoned spent three full days of tense pain and grief and from the effects of poison on the third day which was 25th of Rajab 183 Hijri (799 AD) his spirit flew to the Garden of Eden and joined with his immaculate fathers and forefathers. Since the news of his death was given to Haroon, he ordered to take his blessed body out of jail and placed in general visage and his blessed face to be kept open and said to the people: come observe that Musa ibn Jafar died naturally and nobody tormented him and took testimony of the people of the natural death of His Holiness but those who saw the appearance of the dead body understood that His Holiness was poisoned, but nobody had the courage to express. Then his blessed body was brought to Baghdad by a ferry-boat and allowed a group of Shiites who had gathered to bury his blessed body with honor and great respect and with extensive funeral and grand procession. About the period of imprisonment of His Holiness Musa bin Jafar (AS), there is a lot of disagreement from 4 years to 7 years and it is also said and written 8 years, His Holiness Musa before his arrest had introduced Ali Al Reza his esteemed son as his vicegerent and imamate of the people to his special disciples and recommended them to obey him. His blessed age during the time of his martyrdom was 55 years and 4 months and some, and the period of His Holiness’ Imamate was 34 years and some months.
Marriage and Children of His Holiness:
His Holiness did not have a non-bondswoman wife and the mothers of his respected children all were Omme Walads and bondswomen. His children are written as thirty seven, out of which 18 boys as follows:
1) His Holiness Ali bin Musa al Reza
And daughters of His Holiness were 19:
1) Fatima Kobra
2) Fatima Soghra
5) Omme Abiha
6) Roqaya Soghra
8) Omme Jafar
16) Omme Salama
18) Omme Kulsum
Some Outstanding Companions of His Holiness:
1) Mohammad bin al Afzal Amr al Jaafi who according to the narrations in the book of Bihar-ul-Anwar was the secretary of His Holiness.
2) Ali bin Yaqtin
3) Ali bin Moyad al Saei
4) Mohammad bin Sanan Kufi
5) Mohammad bin Amirolazdi
6) Safvan bin Mehran Jamal Asadi
7) Zarareh bin Aayon
8) Abdullah bin Moqayra
9) Mohammad bin Ali bin Noman al ahwal
10) Aban bin Osman
11) Seyyed al Hamiri who was also His Holiness’ poet.
Contemporary Caliphs of His Holiness:
1) Abu Jafar Abdullah Mamoon
2) Mahdi bin Mansoor
3) Hadi bin Mahdi
4) Haroon al Rashid
 In history, terminologically His Holiness the pre-eminent Commander of the Faithful Ali is referred to as the foremost Abul Hassan, His Holiness Kazem as Abul Hassan the first, His Holiness Reza as Abul Hassan the second and His Holiness Ali Naghi as Abul Hassan the third.
 When a freeman marries a slave woman (bondswoman) and she bears a child. The mother is called Omme Walad and becomes a freewoman.