The Crusader invasions of Egypt (1163–1169) were a series of campaigns undertaken by the Kingdom of Jerusalem to strengthen its position in the Levant by taking advantage of the weakness of Fatimid Egypt. The war began as part of a succession crisis in the Fatimid Caliphate, which began to crumble under the pressure of Muslim Syria ruled by the Zengid dynasty and the Christian Crusader states. While one side called for help from the emir of Syria, Nur ad-Din Zangi, the other called for Crusader assistance. As the war progressed, however, it became a war of conquest. A number of Syrian campaigns into Egypt were stopped short of total victory by the aggressive campaigning of Amalric I of Jerusalem. Even so, the Crusaders generally speaking did not have things go their way, despite several sackings. A combined Byzantine–Crusader siege of Damietta failed in 1169, the same year that Saladin took power in Egypt as vizier. In 1171, Saladin became sultan of Egypt and the crusaders thereafter turned their attention to the defence of their kingdom, which, despite being surrounded by Syria and Egypt, held for another 16 years. Later crusades tried to support the Kingdom of Jerusalem by targeting the danger that was Egypt, but to no avail. Background Following the capture of Jerusalem by the forces of the First Crusade, the Fatimids of Egypt launched regular raids into Palestine against the Crusaders, while Zengi of Syria launched a series of successful attacks against the County of Edessa and Principality of Antioch. The Second Crusade aimed to reverse the gains of Zengi, ironically with an assault on Damascus, Zengi's most powerful rival. The siege failed and forced the Kingdom to turn south for better fortunes. The Fatimid Caliphate in the 12th century was riddled with internal squabbles. In the 1160s, power lay not in the hands of the Fatimid caliph Al-'Āḍid, but in the hands of the vizier of Egypt, Shawar. The situation in Egypt made it ripe for conquest, either by crusaders or by the forces of Zengi's successor, Nur ad-Din. The first Crusader invasion of Egypt culminated in the siege of Ascalon, resulting in the capture of the city in 1154. This meant that the kingdom was now at war in two fronts, but Egypt now had an enemy supply base close at hand. Amalric invades and intervention of Nur ad-Din, 1163–1164 In 1163, Shawar, the ousted Fatimid