Al-Hasan al-A'sam
The Qarmatians repeatedly evicted the Fatimids from Syria and invaded Egypt itself twice, in 971 and 974, before being defeated at the gates of Cairo and driven back.
In the next year, the Fatimids managed to overcome the allies, and concluded a treaty with the Qarmatians that signalled the end of their invasions of Syria.
[1] Power was held collectively among the sons of Abi Sa'id, although the youngest, Abu Tahir Sulayman al-Jannabi, was the dominant figure until his death in 944.
[3][4] This means that, although al-A'sam was the principal military leader of the Qarmatians in their expeditions abroad, in reality power still resided with his uncles, the last of whom, Abu Ya'qub Yusuf, died in 977.
[9] However, modern scholarship has revealed that the Qarmatians were neither loyal partisans of the Fatimids nor, as becomes evident from their behaviour once victorious, were they interested in conquest and conversion of the Syrian territories to their doctrine.
[1][5][12] Through the mediation of the Abbasid caliph al-Muti, the Qarmatians became the nucleus of a broad anti-Fatimid alliance, comprising not only the Qarmatians, but also the Hamdanid ruler of Mosul, Abu Taghlib, the Buyid ruler Izz al-Dawla, the Bedouin tribes of Banu Kilab and Banu Uqayl, and remnants of the Ikhshidid troops.
Jawhar had sent reinforcements, freshly arrived from Ifriqiya, to the city, but their commander, Sa'adat ibn Hayyan, withdrew to Jaffa and adopted a passive stance.
[17] The Qarmatians' detour nevertheless gave Jawhar time to prepare a ditch and wall, at Ayn Shams, north of Fustat, stretching for 10 kilometres (6.2 mi) from the Nile to the Muqattam hills.
[16][18] The Fatimid general called almost the entire population of Fustat to arms, and in two fierce battles on 22 and 24 December 971, despite heavy losses, managed to defeat his opponents.
Soon, the Qarmatian–Bedouin alliance disintegrated due to infighting, allowing the Fatimids to briefly seize again control of Palestine, before the Qarmatians returned later in the year.
From there the Caliph sent al-A'sam a letter, which has survived verbatim as it was included in the material collected by the contemporary anti-Fatimid polemicist Akhu Muhsin.
[26] Al-A'sam occupied the eastern Nile Delta with the main army, but a smaller force under the sharif Akhu Muslim bypassed Cairo and encamped between Asyut and Akhmim, driving out the Fatimid officials and collecting the tax revenues of Middle Egypt for the Qarmatian cause.
[28] Again the Fatimids were forced to a general call to arms of the entire male population of the capital to confront the Qarmatian advance.
[29] On 27 April, al-Mu'izz's son and designated heir Abdallah led the Fatimid army out to confront the Qarmatians at the dry lake bed known as Jubb Umayra or Birkat al-Hajj, just north of Ayn Shams.
Al-A'sam divided his army, sending his brother, al-Nu'man, to face the Fatimid advance, while he himself remained on a height dominating the lake bed.
10,000 Berbers pursued the Qarmatians, cutting off their supply routes, and recovering Palestine and southern Syria before the year was out;[31] while in the south, Akhu Muslim dispersed his small army and barely managed to escape capture himself.
