town, before it was taken by the Knights Templar as a military headquarters. After the Siege of Ascalon ended on 22 August 1153 with a Crusader victory and Damascus was taken by Nūr-ad-Din the next year, uniting all of Syria under Zengid rule. In 1156, Baldwin III was forced into a treaty with Nūr-ad-Din, and later entered into an alliance with the Byzantine Empire. On 18 May 1157, Nūr-ad-Din began a siege on the Knights Hospitaller contingent at Banias, with the Grand Master Bertrand de Blanquefort captured. Baldwin III was able to break the siege, only to be ambushed at Jacob's Ford in June. Reinforcements from Antioch and Tripoli were able to relieve the besieged Crusaders. Bertrand's captivity lasted until 1159, when emperor Manuel I negotiated an alliance with Nūr-ad-Din against the Seljuks. Baldwin III died on 10 February 1163, and Amalric of Jerusalem was crowned as king of Jerusalem eight days later. He undertook a series of four invasions of Egypt from 1163 to 1169, taking advantage of weaknesses of the Fatimids. Nūr-ad-Din's intervention in the first invasion allowed his general Shirkuh, accompanied by his nephew Saladin, to enter Egypt. Shawar, the deposed vizier to the Fatimid caliph al-Adid, allied with Amalric I, attacking Shirkuh at the second siege of Bilbeis beginning in August 1164, following Amalric's unsuccessful first siege in September 1163. This action left the Holy Land lacking in defenses, and Nūr-ad-Din defeated a Crusader forces at the Battle of Harim in August 1164, capturing most of the Franks' leaders. After the sacking of Bilbeis, the Crusader-Egyptian force was to meet Shirkuh's army in the indecisive Battle of al-Babein on 18 March 1167. In 1169, both Shawar and Shirkuh died, and al-Adid appointed Saladin as vizier. Saladin, with reinforcements from Nūr-ad-Din, defeated a massive Crusader-Byzantine force at the siege of Damietta in late October. This gained Saladin the attention of the Assassins, with attempts on his life in January 1175 and again on 22 May 1176. Baldwin IV of Jerusalem became king on 5 July 1174 at the age of 13. As a leper he was not expected to live long, and served with a number of regents, and served as co-ruler with his cousin Baldwin V of Jerusalem beginning in 1183. Baldwin IV, Raynald of Châtillon and the Knights Templar defeated Saladin at the celebrated Battle of Montgisard on 25 November 1177. In June 1179, the