Abu Nasr Fath al-Qal'i, also known by his laqab (honorific epithet) of Mubarak al-Dawla wa-Sa'id-ha (Blessed and Happiness of the State), was the governor of the Citadel of Aleppo during the reign of Emir Mansur ibn Lu'lu' (r. 1008-1016). In 1016, he rebelled against Mansur, in likely collusion with Salih ibn Mirdas, forcing Mansur to flee. After a few months, Fath relinquished control of Aleppo to the Fatimid Caliphate, marking the beginning of direct Fatimid rule over the city. Afterward, he held posts in Tyre, then Jerusalem. As governor of Jerusalem, Fath helped the Fatimid general Anushtakin al-Dizbari suppress a rebellion by the Jarrahids in 1024-1025 and maintained order between the Rabbinate and Karaite Jewish sects during the Hoshana Rabbah festivals at the Mount of Olives in 1029 and 1030.