Baldwin, crippled by leprosy, can no longer function as monarch by September 1183.
Guy of Lusignan, who had married Baldwin's sister Sibylla of Jerusalem in 1180, is appointed regent.
Saladin on August 24, 1183, returns to Damascus, having conquered Aleppo and several cities in Mesopotamia for his empire.
He mounts a major invasion in September of the Kingdom of Jerusalem.
Crossing the Jordan River, the Ayyubid host plunders the abandoned town of Baisan.
Continuing west, up the Jezreel Valley, Saladin establishes his army near some springs about eight kilometers southeast of Al-Fule.
At the same time, the Muslim leader sends out numerous columns to damage as much property as possible.
The raiders destroy the villages of Jenin and Afrabala, attack the monastery on Mount Tabor and wipe out a contingent from Kerak that is trying to join the Crusader field army.
Guy of Lusignan, expecting an attack, musters the Crusader host at Sephoria.
When intelligence reports detect Saladin's invasion route, Guy marches the field army to the small castle at Al-Fule (La Fève).
His army is swollen by pilgrims and Italian sailors to a size of thirteen hundred horsemen and over fifteen thousand infantry.
The Frankish army advances in its usual fashion toward the water points at Ain Jalut And Ain Tuba'un (Tubania).
The exact formation cannot be reconstructed, except that the infantry spearmen and bowmen kept the Turkish horse archers at a respectable distance while the mounted knights launched local charges to drive away any Saracens who approached too closely.
Muslim chroniclers mention how Saladin's Mamluks led by Jorduk an-Nuri and Jawili were faced with an unexpected crusader attack, but they fortified themselves at a base of a mountain and caused the crusaders to retire.
Saladin, unable to halt his enemies or to provoke them to fight a pitched battle, withdraws his army from the springs and moves downstream.
The Latin army camps around the springs and remains passive for eight days, refusing battle.
The Saracens try to incite the Franks into an attack while intercepting the Crusaders' supply convoys.
Since the local Crusaders have brought provisions for only three days while the pilgrims and the sailors have brought none, the supply situation soon becomes critical.
By great good luck, the Latin soldiers find quantities of fish at Ain Tuba'un and this prevents them from starving until some food convoys get through the Ayyubid blockade.
Saladin then moves toward Mount Tabor, hoping to lure the Franks into an ambush.
Guy instead retreats to Al-Fule.
During this move, the Ayyubid army quickly returns and pounces on the Crusaders again, but they are unable to halt or disrupt the march.
Saladin, also short of supplies, concludes the campaign.
At this, Guy marches back to his main base at Sephoria.
Following long-standing Crusader policy, Guy has successfully thwarted Saladin's invasion by preventing him from capturing any strongholds and by keeping the field army intact.
However, as in 1182, the Saracen raiders have caused extensive damage to crops and villages.
Guy is harshly criticized for failing to fight a major battle when in command of such a large host.
Others, mostly native barons such as Raymond III of Tripoli, supportshis cautious strategy, pointing out that Saladin's army had been drawn up on rough ground, unsuitable for a Frankish heavy cavalry charge.
Guy soon after this battle loses his position as regent.