In the Battle of Marj Ayyun, alternately Marj Ayyoun, an Ayyubid army commanded by Saladin defeated a Crusader army led by King Baldwin IV of Jerusalem on June 10, 1179. The Christian king, who was crippled by leprosy, narrowly escaped being captured in the rout.
In 1179 Saladin again invaded the Crusader states, from the direction of Damascus. He based his army at Banias and sent raiding forces to despoil villages and crops near Sidon and the coastal areas. Farmers and townpeople impoverished by Saracen raiders would be unable to pay rent to their Frankish overlords. Unless stopped, Saladin's destructive policy would weaken the Crusader kingdom.
In response, Baldwin moved his army to Tiberias on the Sea of Galilee. From there he marched north-northwest to the stronghold of Safed. Continuing in the same direction, he reached Toron castle (Tebnine), about 13 miles (21 km) east-southeast of Tyre. Together with the Knights Templar led by Odo of St Amand and a force from the County of Tripoli led by Count Raymond III, Baldwin moved northeast.
From the eastern side of the coastal range, the Crusaders saw Saladin's tents in the distance. Baldwin and his nobles decided to descend to the plain and attack at once. As the Frankish army moved downhill, the mounted troops soon outstripped the foot soldiers. After a few hours' delay, the Crusader army reassembled, then encountered and easily defeated the Saracen raiding forces, who were returning from their forays.
Believing the battle won, the Franks let their guard down. Raymond's knights and Odo of St Amand's Templars moved onto some high ground between the Marj Ayyun and the Litani River. The Crusader infantry rested from their hurried march earlier in the day.
Suddenly, Saladin's main army attacked the unprepared Crusaders, defeating them badly. Observers of the time blamed the defeat on Odo of St Amand, who was captured in the battle. King Baldwin barely escaped capture; unable to mount a horse because of his crippling disease, he was carried to safety by a knight as his bodyguard cut a path through the Saracens. Many Frankish survivors of the struggle fled to shelter at Beaufort Castle (Qala'at ash-Shaqif Arnoun) about 5 miles (8.0 km) southwest of the battlefield.
Saladin immediately took advantage of his victory by destroying the newly built Le Chastellet stronghold at the Battle of Jacob's Ford. In the years after Marj Ayyun, the Frankish leaders became more cautious and the next two campaigns of note, the Battle of Belvoir Castle (1182) and the Battle of Al-Fule (1183) were strictly defensive in nature.
Soleim Al-Razi was a Muslim physician who compassionately treated wounded crusaders captured by the Muslim forces.