al-Malik al-Adil Nur ad-Din Abu al-Qasim Mahmud Ibn 'Imad ad-Din Zangi (February 1118 – May 15, 1174), also known as Nur ed-Din, Nur al-Din, etc. (in Arabic: نور الدين Nūr ad-Dīn; ie Light of the Faith) was a member of the Zengid dynasty who ruled Syria from 1146 to 1174.
Nur ad-Din sought to make alliances with his Muslim neighbours in northern Iraq and Syria in order to strengthen the Muslim front against their western enemies. In 1147 he signed a bilateral treaty with Mu'in ad-Din Unur, governor of Damascus; as part of this agreement, he also married Mu'in ad-Din's daughter Ismat ad-Din Khatun. Together Mu'in ad-Din and Nur ad-Din besieged the cities of Bosra (see Battle of Bosra) and Salkhad, which had been captured by a rebellious vassal of Mu'in ad-Din named Altuntash, but Mu'in ad-Din was always suspicious of Nur ad-Din's intentions and did not want to offend his former crusader allies in Jerusalem, who had helped defend Damascus against Zengi. To reassure Mu'in ad-Din, Nur ad-Din curtailed his stay in Damascus and turned instead towards the Principality of Antioch, where he was able to seize Artah, Kafar Latha, Basarfut, and Balat.
In 1148, the Second Crusade arrived in Syria, led by Louis VII of France and Conrad III of Germany. They decided to attack Damascus, despite the former alliance the city had made with the Kingdom of Jerusalem. Mu'in ad-Din reluctantly called for help from Nur ad-Din; the crusader siege lasted only four days before Nur ad-Din arrived.
Nur ad-Din took advantage of the failure of the crusade to prepare another attack against Antioch. In 1149, he launched an offensive against the territories dominated by the castle of Harim, situated on the eastern bank of the Orontes, after which he besieged the castle of Inab. The Prince of Antioch, Raymond of Poitiers, quickly came to the aid of the besieged citadel. The Muslim army destroyed the crusader army at the Battle of Inab, during which Raymond was killed. Raymond's head was sent to Nur ad-Din, who sent it along to the caliph in Baghdad. Nur ad-Din marched all the way to the coast and expressed his dominance of Syria by symbolically bathing in the Mediterranean Sea. He did not, however, attack Antioch itself; he was content with capturing all Antiochene territory east of the Orontes and leaving a rump state around the city, which in any case soon fell under the suzerainty of the Byzantine Empire. In 1150, he defeated Joscelin II for a final time, after allying with the Seljuk Sultan of Rüm, Mas'ud (whose daughter he also married). Joscelin was blinded and died in his prison in Aleppo in 1159. In the Battle of Aintab, Nur ad-Din tried but failed to prevent King Baldwin III of Jerusalem's evacuation of the Latin Christian residents of Turbessel. In 1152 Nur ad-Din briefly captured Tortosa after the assassination of Raymond II of Tripoli.
After the failure of the Second Crusade, Mu'in ad-Din had renewed his treaty with the crusaders, and after his death in 1149 his successor Mujir ad-Din followed the same policy. In 1150 and 1151 Nur ad-Din besieged the city, but retreated each time with no success, aside from empty recognition of his suzerainty. When Ascalon was captured by the crusaders in 1153, Mujir ad-Din forbade Nur ad-Din from travelling across his territory. Mujir ad-Din, however, was a weaker ruler than his predecessor, and he also agreed to pay an annual tribute to the crusaders in exchange for their protection. The growing weakness of Damascus under Mujir ad-Din allowed Nur ad-Din to overthrow him in 1154, with help from the population of the city. Damascus was annexed to Zengid territory, and all Syria was unified under the authority of Nur ad-Din, from Edessa in the north to the Hauran in the south. He was cautious not to attack Jerusalem right away, and even continued to send the yearly tribute established by Mujir ad-Din; meanwhile he briefly became involved in affairs to the north of Mosul, where a succession dispute in the Sultanate of Rüm threatened Edessa and other cities.
In 1157 Nur ad-Din besieged the Knights Hospitaller in the crusader fortress of Banias and routed a relief army from Jerusalem, but he fell ill that year and the crusaders were given a brief respite from his attacks. In 1159 the Byzantine emperor Manuel I Comnenus arrived to assert his authority in Antioch, and the crusaders hoped he would send an expedition against Aleppo. However, Nur ad-Din sent ambassadors and negotiated an alliance with the emperor against the Seljuks, much to the crusaders' dismay. Nur ad-Din, along with the Danishmends of eastern Anatolia, attacked the Seljuk sultan Kilij Arslan II from the east the next year, while Manuel attacked from the west. Later in 1160, Nur ad-Din captured the Prince of Antioch, Raynald of Chatillon after a raid in the Anti-Taurus mountains; Raynald remained in captivity for the next sixteen years. By 1162, with Antioch under nominal Byzantine control and the crusader states further south powerless to make any further attacks on Syria, Nur ad-Din made a pilgrimage to Mecca. Soon after he returned, he learned of the death of King Baldwin III of Jerusalem, and out of respect for such a formidable opponent he refrained from attacking the crusader kingdom: William of Tyre reports that Nur ad-Din said “We should sympathize with their grief and in pity spare them, because they have lost a prince such as the rest of the world does not possess today.”
Shawar immediately expelled Shirkuh and allied with Amalric, who arrived to besiege Shirkuh at Bilbeis. Shirkuh agreed to abandon Egypt when Amalric was forced to return home, after Nur ad-Din attacked Antioch and besieged the castle of Harenc. There, Nur ad-Din routed the combined armies of Antioch and Tripoli, but refused to attack Antioch itself, fearing reprisals from the Byzantines. Instead he besieged and captured Banias, and for the next two years continually raided the frontiers of the crusader states. In 1166 Shirkuh was sent again to Egypt. Amalric followed him at the beginning of 1167, and a formal treaty was established between Amalric and Shawar, with the nominal support of the caliph. The crusaders occupied Alexandria and Cairo and made Egypt a tributary state, but Amalric could not hold the country while Nur ad-Din still held Syria, and he was forced to return to Jerusalem.
In 1168 Amalric sought an alliance with Emperor Manuel and invaded Egypt once more. Shawar's son Khalil had had enough, and with support from Caliph al-Adil requested help from Nur ad-Din and Shirkuh. At the beginning of 1169 Shirkuh arrived and the crusaders once more were forced to retreat. This time Nur ad-Din gained full control of Egypt. Shawar was executed and Shirkuh was named vizier of the newly conquered territory, later succeeded by his nephew Saladin. One last invasion of Egypt was launched by Amalric and Manuel, but it was disorganized and came to nothing.
However, when Nur ad-Din was on the verge of invading Egypt in 1174, he was seized by a fever due to complications from a peritonsillar abscess, and died at the age of 59. His young son As-Salih Ismail al-Malik became his legitimate heir, and Saladin declared himself his vassal, although he really planned to unify Syria and Egypt under his own rule. He married Nur ad-Din's widow, defeated the other claimants to the throne and took power in Syria in 1185, finally realizing Nur ad-Din's dream.
Nur ad-Din also constructed universities and mosques in all the cities he controlled. These universities were principally concerned with teaching the Quran and Hadith. Nur ad-Din himself enjoyed to have specialists read to him from the Hadith, and his professors even awarded him a diploma in Hadith narration. He had free hospitals constructed in his cities as well, and built caravanserais on the roads for travellers and pilgrims. He held court several times a week so that people could seek justice from him against his generals, governors, or other employees who had committed some crime. In the Muslim world he remains a legendary figure of military courage, piety, and modesty. Sir Steven Runciman said that he loved, above all else, justice.
The Damascene chronicler Ibn al-Qalanisi generally speaks of Nur ad-Din in majestic terms, although he himself died in 1160, and unfortunately did not witness the later events of Nur ad-Din’s reign.