442 A HISTORY OF THE CRUSADES I 
 
ad-Din Muliarnmad, the ruler of Baalbek, to assume the rule of the city.
The latter accepted the invitation. Meanwhile, Mu~in-adDIn Unur expelled
another brother and claimant, Bahrãm-Shãh, who thereupon repaired
to Aleppo to enlist Zengi's aid. He was assisted in his quest by his mother,
Zengi's wife, who urged her spouse to avenge her dead son. Determined to
find in this incident an occasion whereby he could dominate the country,
Zengi quickly responded by marching on Damascus. Finding the Damascenes on
guard and determined to repel him, he changed his plans and began an investment
of Baalbek, which Mu9n-ad-Din Unur had recently received as a fief from Jamal-ad-Din
Muliammad on August 20. The entente of the preceding summer was no more and
Zengi's ambitions were apparent to all. 
 Undaunted by this crisis, Mu9n-ad-DIn Unur resumed the negotiations with
the Franks for an alliance which he had unsuccessfully carried on in 1133
and 1138. Appealing for their assistance against a common foe, he dispatched
envoys to Fuik with a promise of the cession of Banyas as soon as Zengi had
been driven from Damascus. Recognizing the cogency of Mu9n-ad-DIn Unur's
arguments and attracted by his promise of Banyas, which was now controlled
by an emir friendly to Zengi, the Frankish leaders agreed to his proposal.

 Meanwhile, Zengi's military progress continued for a time unabated with
the capture of Baalbek in October and with the routing of Mu~in-ad-DIn Unur's
contingents on the outskirts of Damascus in December. Yet final victory eluded
his grasp. Jamalad-Din Muhammad at first entertained favorably his offer
of Baalbek and Homs in exchange for Damascus, but changed his mind when his
advisers pointed out Zengi's untrustworthiness. Even Jamal-ad-Din Muhammad's
death on March 29, 1140, with all its potentialities for governmental paralysis
in Damascus, proved to be only a temporary gain for him, for Mu~In-ad-Din
Unur and other Damascene leaders kept tight control of affairs and appointed
the dead man's son Mujir-ad-DIn Abak to fill the vacant post. Hoping to capitalize
on the supposed discords between the Damascene leaders, Zengi now attacked
Damascus, but was met by stubborn and united resistance. Even the Franks
eluded him. Learning of the recently contracted Franco-Damascene alliance
and seeking to battle the Franks before they united with the Damascenes,
he abandoned his siege of Damascus on May 4 and advanced into the Hauran
to attack the Franks. When they failed to appear he returned to the Damascus
country on