Battle of Hattin - Wikipedia

On July 3, 1187, in the Battle of Horns of Hattin, Saladin, Sultan of Egypt and Syria, destroyed Jerusalem's crusader army. From the article:

"In late May Saladin assembled the largest army he had ever commanded, around 30,000 men including about 12,000 regular cavalry. He inspected his forces at Tell-Ashtara before crossing the River Jordan on June 30. The opposing Crusader army amassed at La Saphorie; it consisted of around 20,000 men, including 1,200 knights from Jerusalem and Tripoli and 50 from Antioch. Though the army was smaller than Saladin's it was still larger than those usually mustered by the Crusaders.[4] After reconciling, Raymond and Guy met at Acre with the bulk of the crusader army. According to the claims of some European sources, aside from the knights there was a greater number of lighter cavalry, and perhaps 10,000 foot soldiers, supplemented by crossbowmen from the Italian merchant fleet, and a large number of mercenaries (including Turcopoles) hired with money donated to the kingdom by Henry II, King of England.[14] Also the army's standard was the relic of the True Cross,[4] carried by the Bishop of Acre, who was there in place of the ailing Patriarch Heraclius.

On July 2, Saladin, who wanted to lure Guy into moving his field army away from their encampment by the springs at La Saphorie, personally led a siege of Raymond's fortress of Tiberias while the main Muslim army remained at Kafr Sabt. The garrison at Tiberias tried to pay Saladin off, but he refused, later stating that "when the people realized they had an opponent who could not be tricked and would not be contented with tribute, they were afraid lest war might eat them up and they asked for quarter...but the servant gave the sword dominion over them." The fortress fell the same day. A tower was mined and, when it fell, Saladin's troops stormed the breach killing the opposing forces and taking prisoners.

Holding out, Raymond's wife Eschiva was besieged in the citadel. As the mining was begun on that structure, news was received by Saladin that Guy was moving the Frank army east. The Crusaders had taken the bait.

Guy's decision to leave the secure base provided by his well-watered assembly point at La Saphorie, was the result of a Crusader war council held the night of July 2. Though reports of what happened at this meeting are biased due to personal feuds among the Franks, it seems Raymond argued that a march from Acre to Tiberias was exactly what Saladin wanted while La Saphorie was a strong position for the Crusaders to defend. Furthermore, Guy shouldn't worry about Tiberias, which Raymond held personally and was willing to give up for the safety of the kingdom. In response to this argument, and despite their reconciliation (internal court politics remaining strong), Raymond was accused of cowardice by Gerard and Raynald. The latter influenced Guy to attack immediately.

Guy thus ordered the army to march against Saladin at Tiberias, which is indeed just what Saladin had planned, for he had calculated that he could defeat the crusaders only in a field battle rather than by besieging their fortifications.

Saladin had also unexpectedly gained the alliance of the Druze community based in Sarahmul led by Jamal ad-Din Hajji, whose father Karama was an age-old ally of Nur ad-Din Zangi.[15] The city of Sarahmul had been sacked by the crusaders on various occasions and according to Jamal ad-Din Hajji the crusaders even manipulated the Assassins to kill his three elder brothers."