ruled concurrently in the
Mosul region from 1149 to 1170. Coinage dated to AH 556 (1160-1161 CE). It was Nur ad-Din's dream to unite the various Muslim forces between the
Euphrates and the
Nile to make a common front against the crusaders. In 1149 Saif ad-Din Ghazi died, and a younger brother,
Qutb ad-Din Mawdud, succeeded him. Qutb ad-Din recognized Nur ad-Din as overlord of Mosul, so that the major cities of Mosul and Aleppo were united under one man. Damascus was all that remained as an obstacle to the unification of Syria. 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 Abaq 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 of Syria was unified under the authority of Nur ad-Din, from
Edessa in the north to the
Hauran in the south. Nur ad-Din was generous in his victory, and allowed Abaq to flee with his property, later granting him fiefdoms in the vicinity of
Homs. (1164). "Histoire d'Outremer" (1232–1261) - BL Yates Thompson MS 12 As there was now nothing the crusaders could do in Syria, they were forced to look to the south if they wanted to expand their territory. The capture of
Ascalon had already succeeded in cutting off Egypt from Syria, and Egypt had been politically weakened by a series of very young
Fatimid caliphs. By 1163, the caliph was the young
al-Adid, but the country was ruled by the vizier
Shawar. That year, Shawar was overthrown by
Dirgham; soon afterwards, the
King of Jerusalem,
Amalric I, led an offensive against Egypt, on the pretext that the Fatimids were not paying the tribute they had promised to pay during the reign of Baldwin III. This campaign failed and he was forced to return to
Jerusalem, but it provoked Nur ad-Din to lead a campaign of his own against the crusaders in Syria in order to turn their attention away from Egypt. Nur ad-Din's attack on Tripoli was unsuccessful, but he was soon visited by the exiled Shawar, who begged him to send an army and restore him to the vizierate. Nur ad-Din did not want to spare his own army for a defense of Egypt, but his
Kurdish general
Shirkuh was given permission to invade in 1164. In response, Dirgham allied with Amalric, but the king could not mobilize in time to save him. Dirgham was killed during Shirkuh's invasion and Shawar was restored as vizier. 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 and captured most of the Crusader armies' leadership, including
Raymond III,
Joscelin III and
Bohemond III, leaving three major principalities of the Crusader states leaderless. However, he 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, Nur ad-Din's
Kurdish general
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 due to the unpopularity of the Egyptian alliance with the Crusaders, Shirkuh managed to take Alexandria without bloodshed. The Crusaders besieged Alexandria and famine set in quickly due to the city's limited stores of food. Shirkuh organized a sortie and broke through the enemy lines, leaving command of
Alexandria to his nephew,
Saladin. Ultimately, Amalric could not hold Egypt while Nur ad-Din still held Syria, and he was forced to return to Jerusalem. The siege of Alexandria was lifted, and Shirkuh's forces withdrew from Egypt as well. 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-Adid 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's commander gained full control of Egypt. Shawar was executed and Shirkuh was named vizier of the newly conquered territory. Shirkuh died later that year and was succeeded by his nephew Saladin. One last invasion of Egypt was launched by Amalric and Manuel, but it was disorganized and came to nothing. Saladin continued to swear nominal fealty to Nur ad-Din until his death in 1174, but their relationship became increasingly tense. Saladin was reluctant to join forces with Nur ad-Din against Crusader armies or holdings, withdrawing his own armies on several occasions when Nur ad-Din's forces arrived to assist him. Nur ad-Din's insistence that Saladin abolish the
Shia Caliphate further raised tensions between them. Saladin was reluctant to do so because the authority of the Caliphate in Egypt was a source of legitimacy for his rule. He feared popular backlash, and was bound by friendship and obligation to the Caliph
al-Adid. Nonetheless, Saladin capitulated to Nur ad-Din and the
Fatimid Caliphate was abolished in 1171. ==Death and succession==