An even more important task had been performed in bringing all North Africa into complete subordination. Cultured literary man as the Fatimid Khalif was, he was also a most efficient organizer, and was well served by officials whom he treated with generous confidence. The disciplining of Africa was a necessary preliminary to an expedition outside the bounds of the country, which might well be of protracted duration and uncertain issue. For this he had the assistance of an able general, Abu l-Hasan Jawhar b. ʿAbdullah, commonly known as “Jawhar the Greek scribe,” as he was a liberated slave trained as a secretary, whose father had been subject of the Byzantine Empire. Like Kafur he shows that the slave in Islam was not merely treated as a fellow man, but had a career of ambition open before him, in which his servile origin was no obstacle; even in modern times slaves have risen to high office, and have sometimes married princesses. There was no colour barrier nor any racial feeling: no reluctance was felt at white men being ruled by a negro ex-slave. Marching to the Maghrab, Jawhar joined forces with the Sanhaja chieftain Ziri, who was one of the most faithful allies of the Fatimids (cf. p. 123), and together they advanced upon the Umayyad colonies at Fez and Sijilmasa. These they took and thus prevented the possibility of Spanish interference in Africa for the time. Continuing westwards they reduced the whole Maghrab to the coast. As a sign of the extent of the expedition fish were caught in the ocean, and sent in jars to the Khalif in company with the princes of Fez and Sijilmasa, who were conveyed in an iron cage. The only town left to the Umayyads was Sibta (Ceuta). The Idrisid princes of the far west, descendants of Hasan, the son of ʿAli, were put down, and thus their independent rule which had lasted just over two centuries came to an end. It was a more thorough reduction of the country than had ever been made previously, and when Jawhar returned to Kairawan al-Moʿizz was recognised as the unquestioned ruler of all North Africa. The Khalif determined to entrust the invasion of Egypt to Jawhar, who had so clearly proved his efficiency in the reduction of the Maghrab, but just about this time Jawhar fell ill. Al-Moʿizz was not willing to replace him, and continued his preparations, assembling troops and supplies at Raqada: every day he visited the general who, as soon as his health was sufficiently restored, the order to advance was given.