Siege of Edessa The Siege of Edessa took place from November 28 to December 24 , 1144 , resulting in the fall of the capital of the crusader County of Edessa to Zengi , the atabeg of Mosul and Aleppo . Background . The County of Edessa was the first of the crusader state s to be established during and after the First Crusade . It was also the most northerly , the weakest , and the least populated ; as such , it was subject to frequent attacks from the surrounding Muslim states ruled by the Ortoqids , Danishmends , and Seljuk Turks . Count Baldwin II and future count Joscelin of Courtenay were taken captive after their defeat at the Battle of Harran in 1104 . Joscelin was captured a second time in 1122 , and although Edessa recovered somewhat after the Battle of Azaz in 1125 , Joscelin was killed in battle in 1131 . His successor Joscelin II was forced into an alliance with the Byzantine Empire , but in 1143 both the Byzantine emperor John II Comnenus and the King of Jerusalem Fulk of Anjou died . John II was succeeded by his son Manuel I Comnenus , who had to deal with consolidating power at home against his elder brothers , while Fulk was succeeded by his wife Melisende and his son Baldwin III . Joscelin had also quarreled with Raymond II of Tripoli and Raymond of Antioch , leaving Edessa with no powerful allies . The siege of Edessa . In 1144 , Joscelin was able to make an alliance with Kara Arslan , the Ortoqid ruler of Diyarbakır , against the growing power and influence of Zengi . Joscelin marched out of Edessa with almost his entire army to support Kara Aslan against Aleppo . Zengi , already seeking to take advantage of Fulk ' s death in 1143 , hurried north to besiege Edessa , arriving on November 28 . The city had been warned of his arrival and was prepared for a siege , but there was little they could do while Joscelin and the army were elsewhere . The defense of the city was led by the Latin Archbishop Hugh II , the Armenian Bishop John , and the Jacobite Bishop Basil . John and Basil ensured that none of the native Christians would desert to Zengi . When Joscelin heard of the siege he took the army to Turbessel , knowing that he could never dislodge Zengi without help from the other crusader states . In Jerusalem , Queen Melisende responded to Joscelin ' s appeal by sending an army led by Manasses of Hierges , Philip of Milly , and Elinand of Bures . Raymond of Antioch ignored the call for help , as his army was already occupied against the Byzantine Empire in Cilicia . Zengi surrounded the entire city , realizing that there was no army defending it . He built siege engine s and began to mine the walls , while his forces were joined by Kurdish and Turcoman reinforcements . The inhabitants of Edessa resisted as much as they could , but had no experience in siege warfare ; the city ’ s numerous towers remained unmanned . They also had no knowledge of counter - mining , and part of the wall near the Gate of the Hours collapsed on December 24 . Zengi ' s troops rushed into the city , killing all those who were unable to flee to the Citadel of Maniaces . Thousands more were suffocated or trampled to death in the panic , including Archbishop Hugh . Zengi ordered his men to stop the massacre , although all the Latin prisoners that he had taken were executed ; the native Christians were allowed to live freely . The citadel was handed over on December 26 . One of Zengi ’ s commanders , Zayn ad - Din Ali Kutchuk , was appointed governor , while Bishop Basil , apparently willing to give his loyalty to whoever ruled the city , was recognized as leader of the Christian population . Aftermath . In January 1145 Zengi captured Saruj and besieged Birejik , but the army of Jerusalem had finally arrived and joined with Joscelin . Zengi also heard of trouble in Mosul , and rushed back to take control . There , he was praised throughout Islam as " defender of the faith " and " al - Malik al - Mansur " , the victorious king . He did not pursue an attack on the remaining territory of Edessa , or the Principality of Antioch , as was feared . Joscelin II continued to rule the remnants of the county to the west of the Euphrates from Turbessel , but little by little the rest of the territory was captured by the Muslims or sold to the Byzantines . Zengi was assassinated by a slave in 1146 while besieging Qalat Jabar , and was succeeded in Aleppo by his son Nur ad - Din . Joscelin attempted to take back Edessa following Zengi ' s murder , and recaptured all but the citadel in October 1146 . However , he had no help from the other crusader states , and his poorly planned expedition was driven out of Edessa by Nur ad - Din in November . Joscelin , fearing for the safety of the city ' s Christian Armenians , attempted to break a hole in Nur ad - Din ' s forces through which the natives could flee to safety . However , Joscelin ' s attempt failed and his fears came true when Nur al - Din ' s troops massacred the fleeing Armenians and forced the survivors into slavery . By this time , news of the fall of Edessa reached Europe , and Raymond of Antioch had already sent a delegation including Hugh , Bishop of Jabala , to seek aid from Pope Eugene III . On December 1 , 1145 Eugene issued the papal bull " Quantum praedecessores " calling for the Second Crusade . This crusade was led by Louis VII of France and Conrad III of Germany , but by 1148 it had ended in disaster , and Edessa was never recovered .