576 A HISTORY OF THE CRUSADES I 
 
tamia), and prevent the army of Mosul from crossing the Euphrates. But Farrukh-Shah
was engaged in countering Reginald's schemes of invading Arabia from Kerak
(Krak des Moabites), and Taqiad-DIn was unable to prevent ~Izz-ad-DIn from
entering Aleppo. There he appointed his brother ' Imãd-ad-DIn as governor
of the city, in exchange for Sinjar, and after emptying the contents of its
treasury and arsenal returned to Mosul. Saladin's intense anxiety over the
situation is shown by the succession of letters addressed to the caliph's
council (Arabic, cliwãn), criticizing the conduct of the prince of
Mosul in seizing a province which had been assigned to him while his own
troops were in the very act of protecting the city of the prophet from the
"infidel", complaining that the disputes between the Moslem princes were
hindering the jihad, reasserting his claim to Aleppo on the basis of his
diploma, and declaring that "if the Exalted Commands should ordain that the
prince of Mosul be invested with the government of Aleppo, then it were better
to invest him with all Syria and Egypt as well." The urgent tone of these
letters is no doubt explained partly by the need to counteract the similar
pressure of the partisans of Mosul at Baghdad, but though propaganda points
may be difficult to disentangle from religious zeal there can be no doubt
that Saladin was genuinely in earnest over the stalemate that would follow
from a reunion of Aleppo with Mosul. 
 In May I i8z he left Cairo, accompanied by half of the newly reorganized
army of Egypt, some 5000 troopers in all, and rejoined his lieutenants in
Syria. After an unsuccessful coup de main against Beirut by sea and land,
he marched on Aleppo, fortified in his purpose by the caliph's diploma. But
before investing it, he was visited by Mu~affar-ad-DIn Gokböri, the
governor of Harran, with an urgent invitation to cross the Euphrates and
assurances that he would be welcomed on all sides. Accordingly, since he
was, in fact, by virtue of the caliph's diploma, lawful ruler of the Euphrates
and Khabur provinces, Saladin crossed the Euphrates at the end of September,
and with only scattered opposition occupied the former possessions of Nür-ad-Din
in the Jazira. ~Izzad-DIn attempted to take the field against him, but was
foiled by the opposition of his own officers and the open adhesion to Saladin
of his chief vassal, the Artukid prince of Uisn Kaifã, Nürad-DIn
ibn-Kara-Arslan. The sole result of his action was to supply Saladin with
a valid pretext for advancing on Mosul itself, an action justified by him
in a lengthy despatch to Baghdad, accusing the rulers of Mosul of paying
the Franks to attack him, of op