(July 5, 1029 – January 10, 1094) was the eighth caliph of the Fatimid Caliphate from 1036 until 1094. He was the longest reigning Muslim ruler. He was born in Cairo on 16th Jumada II, 420 AH and at the age of only eight months was declared to succeed his father. His name was Ma'd Abu Tamim, surnamed al-Mustansir bil-Lah "The Asker Of Victory From God". He ascended to the Fatimid Caliphate throne on 15th Shaban, 427/June 13, 1036 at the age of . During the early years of his Caliphate, the state affairs were administered by his mother. His period of Caliphate lasted for 60 years, the longest of all the caliphs, either in Egypt or elsewhere in Islamic states. However, Fatimid power was confined to Egypt due to conquests of Seljuks in Levant and Yemen and Normans in Sicily and Malta.