Drought conditions between 1175 and 1180 prompted the Crusaders to sign a two @-@ year truce with the Muslims , but without Tripoli included in the terms . During the 1180s raids by Christians and Muslims into each other 's territory became more frequent . In 1180 , Saladin ventured into the County of Tripoli , ravaging the area . Unwilling to meet him in open battle , the Crusaders retreated to the relative safety of their fortifications . Without capturing the castles , Saladin could not secure control of the area , and once he retreated the Hospitallers was able to revitalize their damaged lands . The Battle of Hattin in 1187 was a disastrous defeat for the Crusaders : Guy of Lusignan , King of Jerusalem , was captured , as was the True Cross , a relic discovered during the First Crusade . Afterwards Saladin ordered the execution of the captured Templar and Hospitaller knights , such was the importance of the two orders in defending the Crusader states . After the battle , the Hospitaller castles of Belmont , Belvoir , and Bethgibelin fell to Muslim armies . Following these losses , the Order focused its attention on its castles in Tripoli . In May 1188 Saladin led an army to attack Krak des Chevaliers , but on seeing the castle decided it was too well defended and instead marched on the Hospitaller castle of Margat , which he also failed to capture .