He was nicknamed Mansūr al-ʿUbaydī. He claimed to be Fatimid. He ruled the land of al-Maghrib. He is the father of Muʿizz, the founder of the city of Cairo. He himself founded the city of Mansūriyya in the land of al-Maghrib.
Regarding him, Abū Jaʿfar al-Marwazī said: “I accompanied him on the campaign in which he defeated Abū Yazīd al-Ḥāriqī. While we were on the road, at one point his spear fell to the ground. I got down, picked it up, and handed it to him. Then, while walking, I joked with him by reciting the following verse of the poet:
‘He left his staff on the ground and settled there. He relaxed just like a traveler’s relief upon returning home.’
He replied to me: “Why did you not recite the noble verse of Allah? It would have been better if you had recited this:
“And We said to Moses, ‘Throw down your staff.’ And he threw it down, and suddenly it swallowed up what they had fabricated. The truth was established, and what they did was rendered void. So they were defeated there and became humiliated.” (al-Aʿrāf 7:117–120)
I said to him:
– You are the grandson of the Messenger of God (peace and blessings be upon him)’s daughter. You have only mentioned part of what you know. But I have spoken of the best of what I know.
Ibn Ḥallikān said: “Such an incident also occurred concerning ʿAbd al-Malik b. Marwān. He ordered the oppressive Ḥajjāj to build a gate for al-Masjid al-Aqṣā and to inscribe his own name on it. Upon this order, Ḥajjāj built a gate for him and then also had a gate built bearing his own name. After the construction was completed, a lightning bolt struck the gate built in ʿAbd al-Malik’s name and burned it. Thereupon, ʿAbd al-Malik wrote a letter to Ḥajjāj, who was in Iraq, asking his opinion about this matter, and Ḥajjāj sent him the following reply:
“My situation and yours resemble the example given by the Exalted Allah in this noble verse:
“O Muhammad! Recite to them the true story of the two sons of Adam. They each offered a sacrifice, but only one was accepted, and the other was not. The one whose offering was not accepted said, ‘I will surely kill you.’ But his brother said, ‘Indeed, Allah only accepts from the God-conscious (muttaqīn).’” (al-Māʾida 5:27)
The caliph was pleased and satisfied with this reply from Ḥajjāj.”
Mansūr died due to the severe cold witnessed that year. Allah knows best.