Abdullah al-Mahdi Billah

al-Mahdi Billah عبد الله المهدي
Gold coin of Caliph al-Mahdi, Mahdiyya, 926 CE
Caliph of the Fatimid Caliphate
Reign	November 909 – 3 April 934
Predecessor	None (caliphate founded)
Successor	al-Qa'im Bi-Amrillah
Born	873
Died	3 April 934 (aged 61)
Issue	al-Qa'im Bi-Amrillah
Full name (Kunya): Abu Muhammad Given name:Abdallah Laqab: al-Mahdi Billah
Father	Husain (Rabi Abdullah)
Mother	?
Religion	Shia Islam

Abu Muhammad Abdallah al-Mahdi Billah (873 – 4 March 934) (Arabic: أبو محمد عبد الله المهدي بالله‎‎), was the founder of the Ismaili Fatimid Caliphate, the only major Shi'a caliphate in Islam, and established Fatimid rule throughout much of North Africa, Hejaz, Palestine and the Levant.

At the beginning of the Abbasid realm in Baghdad, the Alids faced severe persecution by the ruling party as they were a direct threat to the Abbasid Caliphate. Owing to the political complexities, the forefathers of Imam Abdullah opted to conceal themselves which helped them maintain the Dawa's existence. As a result, these Imams travelled towards the Iranian Plateau to distance themselves from the epicentre of their political difficulties. Al Mahdi's father, Imam al Husain al Mastoor returned in secrecy to Syria and began to control the Dawa's affairs from there in complete concealment. He sent two Da'is of great calibre, Abul Qasim and Abu 'Abdullah Al-Husayn Al-Shi'i to Yemen and North Africa, respectively, to build the foundation for what was to later be the Fatimid Caliphate.

Imam al Husain al Mastoor died soon after the birth of his son, Al Mahdi. A trustworthy system of informers helped Al Mahdi to be updated on developments which were taking place across North Africa which was to be the launching pad of his Empire.