Ch. XVIII THE RISE OF SALADIN 577 
 
pression of their subjects, and finally of appealing to the sworn enemy of
the caliphate, the Selchükid atabeg in Persia. The last accusation is
confirmed by the Mosul sources; in desperation clzz. ad-Din was seeking allies
in every direction, and sent Bahã'-adDin himself to ask for the caliph's
support against Saladin. In response to this appeal, the caliph sent a delegate,
the shaikh ashshuyükh, to mediate between the parties, and for a month
protracted negotiations went on while the siege continued. 
 It must be emphasized that the point at issue in these negotiations was
not at any time Saladin's claim to the physical possession of Mosul, but
the terms on which its prince would adhere to Saladin and send his armies
to cooperate in the war against the Franks. On this first occasion the main
object of the Zengid prince was to retain his suzerainty over Aleppo, and
although Saladin, anxious to reach an agreement, yielded to all his demands
short of this, he refused to ratify the terms. At the urgent intercession
of the shaikh, Saladin agreed to withdraw from Mosul, but refused to continue
the negotiations. The fact that they had been set on foot had severely straifled
the confidence of his new vassals in the J azira, and in order to reassure
them he announced to the diwan his firm determination not to leave the province
until he had completed the conquest of it. 
 He began by besieging ~Izz-ad-Din's brother in Sinjar, with the assistance
of the Artukid Nür-ad-Din. It was surrendered on terms after fifteen
days (December 30), and the garrison was evacuated to Mosul. After Dara also
had been surrendered by its Artukid prince Bahrãm, Saladin went into
winter quarters at Harran. But that he had no intention of relaxing the pressure
upon ~Izz-ad-Din is shown by the stream of correspondence addressed to the
chief ministers at Baghdad and reiterated requests for his recognition as
suzerain of Mosul. Though this was still withheld, his application to receive
the caliph's diploma for Amida (modern Diyarbakir) was granted. In April
clzz..ad.Din made an attempt to rally his remaining allies, but Saladin called
up Taqi-ad-DIn from Hamah, and on his approach the coalition dissolved. Without
waiting for the remainder of his forces he at once laid siege to the all-butimpregnable
fortress of Amida in Diyar-Bakr, in pursuance of a promise made to Nür-ad-DIn.
Its surrender within three weeks set the seal on his reputation; and his
quixotic generosity, both to the defeated governor and in handing it over
with its immense military stores intact to Nflr-ad-Din, disproved once and
for all his enemies' imputations of selfish ambition.