Abul Qasim Husayn ibn Ruh al-Nawbakhti

Abul Qasim Husayn ibn Ruh Nawbakhti (died 937 or 938 AD) was the third of the four deputies appointed by twelfth Shia Imam Muhammad al-Mahdi while he was in the Minor Occultation. He was a native of Qum who migrated to Baghdad during the time of Uthman ibn Sa'id al-Asadi, the first deputy. Al‑Nawbakhti was a companion of the second deputy Abu Jafar Muhammad ibn Uthman and became his agent for several years. After the death of al-Nawbakhti, Abul Hasan Ali ibn Muhammad al-Samarri was appointed as the fourth deputy of Muhammad al-Mahdi.

The birth date of Husayn ibn Ruh al-Nawbakhti is unknown. He was a native of Qum, Iran, who migrated to Baghdad, Iraq, during the time of the first deputy Uthman ibn Sa'id al-Asadi. Husayn ibn Ruh al-Nawbakhti was a member of the al-Nawbakhti family who had a high position among Banu Abbas.

During the Imamah of Hasan al-Askari, the eleventh Imam of Shias, Abul Qasim Husayn ibn Ruh al-Nawbakhti was one of his companions. He was also a companion and supporter of Abu Jafar Muhammad ibn Uthman, the second deputy of Muhammad al-Mahdi, his agent among the Shias and the connection between second deputy and other Shia leaders.

Under the direction of Muhammad al-Mahdi, Husayn ibn Ruh was appointed as the third special deputy by Muhammad ibn Uthman. About three years before Muhammad ibn Uthman's death, to prepare the Shia community to accept Husayn ibn Ruh as the third deputy, Ibn Uthman began directing some of the Shias who were bringing Khums and other religious funds for Muhammad al-Mahdi to Husain ibn Rauh. When he became seriously ill, a group of Shia elite went to see him and about the next deputy; he replied; "Husayn b. Ruh is my successor and the trusted deputy of the Master of the Age. Refer to him in your affairs. I have been commanded by the Imam to designate Husayn b. Ruh in the position of deputyship." When Muhammad ibn Uthman was about to die, he introduced Husayn ibn Ruh as his successor.

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