The death of the Fatimid caliph al-Hakim bi-Amr Allah, kept secret for six weeks, is announced, along with the succession of his son, al-Zahir li-i'zaz Din Allah.

The Fatimid Caliphate, also known as the Fatimid Empire, was a caliphate extant from the tenth to the twelfth centuries CE under the rule of the Fatimids, an Isma'ili Shi'a dynasty. Spanning a large area of North Africa and West Asia, it ranged from the western Mediterranean in the west to the Red Sea in the east. The Fatimids traced their ancestry to the Islamic prophet Muhammad's daughter Fatima and her husband Ali, the first Shi'a imam. The Fatimids were acknowledged as the rightful imams by different Isma'ili communities as well as by denominations in many other Muslim lands and adjacent regions. Originating during the Abbasid Caliphate, the Fatimids initially conquered Ifriqiya. They extended their rule across the Mediterranean coast and ultimately made Egypt the center of the caliphate. At its height, the caliphate included—in addition to Egypt—varying areas of the Maghreb, Sicily, the Levant, and the Hejaz.

Abu Ali al-Mansur, better known by his regnal name al-Hakim bi-Amr Allah, was the sixth Fatimid caliph and 16th Ismaili imam (996–1021). Al-Hakim is an important figure in a number of Shia Ismaili sects, such as the world's 15 million Nizaris and 1–2 million Musta'lis, in addition to 2 million Druze.

Abū al-Ḥasan ʿAlī ibn al-Ḥākim, better known with his regnal name al-Ẓāhir li-Iʿzāz Dīn Allāh, was the seventh caliph of the Fatimid dynasty (1021–1036). Al-Zahir assumed the caliphate after the disappearance of his father al-Hakim bi-Amr Allah.

March 26 is the 85th day of the year in the Gregorian calendar; 280 days remain until the end of the year.