The Four Deputies (Arabic: النواب الأربعة, al-Nuwāb al-Arbaʿa) were the four individuals who are believed by the Twelvers to have successively represented their twelfth Imam, Muhammad al-Mahdi, during his Minor Occultation (874–941 CE). They were also known as the Gates (Arabic: أبواب, romanized: abw'ab), the Sufaraʾ (Arabic: سفراء, lit. 'emissaries'), or the Wukalaʾ (Arabic: وكلاء, lit. 'agents').

Until their deaths, the tenth and eleventh Shia Imams (Ali al-Hadi and Hasan al-Askari, respectively) were held under close surveillance in the garrison town of Samarra by the Abbasids, who are often responsible in Shia sources for poisoning the two Imams. The two Imams witnessed the deterioration of the Abbasid caliphate, as the imperial authority rapidly transitioned into the hands of the Turks, particularly after al-Mutawakkil.

Contemporary to the tenth Imam, the Abbasid al-Mutawakkil violently prosecuted the Shia, partly due to the renewed Zaydi opposition. The restrictive policies of al-Mutawakkil towards the tenth Imam were later adopted by his son, al-Mu'tamid, who is reported to have kept the eleventh Imam under house arrest without any visitors. Instead, al-Askari is known to have mainly communicated with his followers through a network of representatives. Among them was Uthman ibn Sa'id, who is said to have disguised himself as a seller of cooking fat to avoid the Abbasid agents, hence his nickname al-Samman.

Tabatabai suggests that these restrictions were placed on al-Askari because the caliphate had come to know about traditions among the Shia elite, predicting that the eleventh Imam would father the eschatological Mahdi.

Immediately after the death of al-Askari in 260 (874), Uthman al-Amri (d. 880) claimed that the eleventh Imam had a young son, named Muhammad, who had entered a state of occultation (ghayba) due to the Abbasid threat to his life. According to a Shia tradition attributed to the sixth Imam, Ja'far al-Sadiq, this threat was specific to Muhammad al-Mahdi, who was expected to rise, unlike his predecessors who often practiced religious dissimulation (taqiya) and were politically quiescent.

As the special agent of al-Askari, Uthman also claimed that he had been appointed to represent the son of the eleventh Imam. Twelver sources detail that Muhammad al-Mahdi made his only public appearance to lead the funeral prayer for his father instead of his uncle, Ja'far. It is also said that the occultation took place in the family home in Samarra, where currently a mosque stands, under which there is a cellar (sardab) that hides a well (Bi'r al-Ghayba, lit. 'well of the occultation'). Into this well, al-Mahdi is said to have disappeared.

Thus began a period of about seventy years, later termed the Minor Occultation (al-ghaybat al-sughra, 260-329 AH, 874–940 CE), during which it is believed that four successive agents who represented the Hidden Imam. An agent (wakil) was variously called deputy (na'ib), emissary (safir), and gate (bab).

Abu Muhammad Uthman ibn Sa'id al-Asadi was a close associate of the tenth Imam, Ali al-Hadi. It is reported that he was eleven when he first served as an agent for this Imam. After the death of al-Hadi in 254 (868), his successor, al-Askari, appointed Uthman as a representative in 256 (869–70). It also seems certain that Uthman became the closest associate of the eleventh Imam. Both al-Hadi and al-Askari are said to have praised Uthman as highly trustworthy. As a representative of the two Imams, Uthman disguised himself as a seller of cooking fat to avoid the Abbasid agents, hence his nickname al-Samman. It is reported that he collected religious donations, hid them in the containers of cooking fat, and delivered them to al-Askari.