The Abbasid caliph Kadir billah (d. 422/1031) got his rule dwindling before his eyes. He saw Baghdad yielding its position of prestige as the seat of culture and science to Cairo, and he found himself a virtual prisoner of the Buwahids, while the Fatimid Caliph al-Hakim was ruling powerfully and absolutely. Ibn al-Jawzi (d. 597/1200) writes in "al-Muntazam fi Tarikh al-Muluk" (Hyderabad, 1840, 7th vol., p. 237) that, "The Shia of Iraq had looked to al-Hakim as their desired Caliph in 398/1008 in Baghdad, and during a quarrel with the Sunnis, they shouted slogans, Ya Hakim, Ya Mansur in favour of al-Hakim."
In 401/1010, Mutamad ad-Dawla Qirwash bin Maqallid (d. 444/1052), the chief of the Uqayl tribe and governor of Mosul, Madain, Anbar and Kufa acknowledged the Fatimid Caliphate instead of the Abbasids, and started the Fatimid khutba and coinage. In the same year, Ali bin Mazid Asadi (d. 408/1018), the chief of the Asad tribe also proclaimed his loyalty to al-Hakim and had the Fatimid khutba read in Hilla and the districts he governed.
The Abbasid caliph Kadir billah alarmed over the prosperity of Egypt and growing influence of the Fatimids inside his empire, therefore, he attempted to combat with al-Hakim by another cowardice tool. He gathered a number of Shia and Sunni theologians and jurists to his court in 402/1011 and ordered them to prepare a forged manifesto that the Fatimid claim of Alid descent was false. Ibn Khaldun (1332- 1406) writes in "Muqaddimah" (tr. Franz Rosenthal, London, 1958, 1st vol., pp. 45-6) that, "The judges in Baghdad eventually prepared an official statement denying the Alid origin (of the Fatimids). The statement was witnessed by a number of prominent men, among them the Sharif ar-Radi and his brother al-Murtada, and Ibn al-Bathawi. Among the religious scholars were Abu Hamid al-Isfarayini, al-Quduri, as- Saymari, Ibn al-Akfani, al-Abiwardi, the Shia jurist Abu Abdullah bin an-Numan, and other prominent Muslims in Baghdad. The event took place one memorable day in the year 402/1011 in the time of (the Abbasid caliph) al-Qadir. The testimony was based upon heresy, on what people in Baghdad generally believed. Most of them were partisans of the Abbasids who attacked the Alid origin (of the Fatimids). The historians reported the informations as they had heard it. They handed down to us just as they remembered it. However, the truth lies behind it. Al-Mutadid's letter concerning Ubaydallah (al-Mahdi) to Aghlabid in al-Qayrawan and the Midrarid in Sijilmasah, testifies most truthfully to the correctness of the origin (of the Fatimids) and proves it most clearly. Al-Mutadid was better qualified than anyone else to speak about the genealogy of the Prophet's house." Ibn Taghri Birdi (d. 874/1470) writes in his "al-Nujum al-Zahira fi Muluk wa al-Qahira" (Cairo, 1929, 4th vol., p. 236) that, "The Abbasid caliph hired theologians and paid them large sum of money to write books condemning the Fatimid cause and their doctrine."
We have three accredited Sunni historians, Ibn Khaldun (1332-1406), Abul Fida (1273-1331) and Makrizi (1363-1442), who were not under the pressure or influence of either the Abbasids or the Fatimids. These historians concur that the Fatimids of Egypt were the direct descendants of Ali and Fatima. The Abbasid false propaganda, however, discrediting the Fatimid lineage has been falsified through accredited sources and arguments, vide "Genealogy of the Aga Khan" by Mumtaz Ali Tajddin Sadik Ali, Karachi, 1990.