of al-Hadi, minted in
Haruniya in 786/7 Shortly after al-Mahdi died in July 785, Husayn and his followers rose in revolt at Medina, hoping to take advantage of the as yet unstable position of al-Mahdi's successor,
al-Hadi. The 10th-century historian
al-Tabari records several traditions that suggest that the immediate cause of the revolt was a quarrel between Husayn and the Abbasid governor of Medina,
Umar ibn Abd al-Aziz ibn Abdallah, known as al-Umari. Al-Umari tried to regulate the Alids' movements in the city, and had three men, including Abu'l-Zift, a son of Muhammad al-Nafs al-Zakiyya,
flogged and publicly humiliated for flouting the
Islamic prohibition against the consumption of alcohol; this caused outrage among the Alids. The situation grew worse when it was discovered that Abu'l-Zift, for whom Husayn had vouched together with
Yahya ibn Abdallah (a half-brother of Muhammad al-Nafs al-Zakiyya), had fled the city. In the ensuing confrontation with al-Umari, Yahya ibn Abdallah and the governor exchanged insults and threats, making the situation untenable for Husayn and his followers. While this may have been the immediate spark for the uprising, from the subsequent passages of al-Tabari it is evident that a revolt had been planned for some time. Preparations included the recruitment of
Kufans who were secretly lying in wait in the city, and the hope of assistance by sympathizers who performed the
Hajj pilgrimage. The motivation for the revolt is unclear; later Shi'a writers claim that it resulted from the anti-Alid stance of the new caliph, al-Hadi, but given the short interval since al-Hadi's accesstion, this is unlikely; however, Veccia Vaglieri suggests that there are indications that in his final years al-Mahdi himself had turned from a conciliatory policy to hostility towards the Alids, causing great discontent among the Shi'a. Having quarreled with the governor, the conspirators decided to move on the next morning (probably 16 May). About 26 Alids and some of their supporters gathered at the
Mosque of the Prophet, where Husayn took the pulpit dressed in white and wearing a white turban. The rebels reportedly forced the
muezzin to pronounce the
call to the morning prayer in the Shi'a wording. Most people turned away when they saw Husayn in the pulpit, but his followers started arriving and
swearing allegiance to him as caliph and
imam and as , 'the One pleasing to God from the house of Muhammad'. The appellation was evidently adopted as Husayn's
regnal title in the fashion of the Abbasid caliphs. Whether out of the rivalry between the Hasanid and
Husaynid branches, or because they thought that the uprising was doomed to failure, two of the Alids present refused their support. One of them,
Musa ibn Ja'far al-Kadhim, who is considered as the seventh imam by the
Twelver Shi'a, reportedly warned Husayn that his actions would only result in his death. In the meantime, Yahya ibn Abdallah went to arrest al-Umari at his residence, which adjoined the mosque. Alarmed by the Shi'a call to prayer, al-Umari had already gone into hiding. The assembled rebels were soon confronted by about 200 men from the local Abbasid garrison, with al-Umari and a certain Khalid al-Barbari, supervisor of the state domains at Medina, at their head. Khalid charged forward, aiming to kill Husayn, but was cut down by Yahya ibn Abdallah and his brother
Idris; taking heart, the rebels attacked the Abbasid troops, who fled. With the Abbasid partisans repelled, Husayn addressed his followers, concluding his speech with a declaration and oath: The revolt failed to find many adherents; according to al-Tabari, "the people of Medina locked their doors". Next morning, the fighting between the partisans of the Alids (, the 'wearers of white') and the Abbasids (, the 'wearers of black') spread throughout the city, with the Abbasids driving the Alids back. Fresh Abbasid troops under Mubarak al-Turki arrived next day, heartening the Abbasid partisans. After another day of fierce fighting, interrupted only during the hot noon hours, the Alids were confined to the area of the mosque, while the Abbasids used the nearby governor's residence as their base. The confrontation lasted for eleven days, during which the Alids, with their failure to secure the city evident, gathered supplies for travel. With about 300 followers, Husayn left the city on 28 May 786. In their wake, they left the mosque in a state of filth, defiled with the bones of the animals the beleaguered Alids had been eating, and its curtains cut up to make
kaftans, leading to general indignation among the Medinese. ==Confrontation at Fakhkh==