Saladin destroyed the army of the Kingdom of Jerusalem at Hattin in 1187, opening the way to his recapture of Jerusalem and triggering the Third Crusade.
The Battle of Hattin was fought on 4 July 1187 between the army of the Ayyubid sultan Saladin and the field army of the Kingdom of Jerusalem under King Guy of Lusignan. It was the most catastrophic defeat in the history of the crusader states.
Saladin drew the crusaders into waterless country near the Horns of Hattin, surrounded and destroyed their army, and captured the king and the relic of the True Cross. The victory left the kingdom defenceless and led directly to Saladin's recapture of Jerusalem and to the calling of the Third Crusade.
By the 1180s Saladin had united Egypt and Muslim Syria and framed the war against the crusader states as a jihad to recover Jerusalem. Repeated truce-breaking raids by Reynald of Châtillon against Muslim caravans and the pilgrim routes gave him both motive and justification for an all-out campaign.
In 1187 Saladin besieged Tiberias to draw out the crusader army. The kingdom's leaders were divided: Raymond III of Tripoli argued against marching across dry country in high summer, but the faction led by Reynald and the Templar master persuaded King Guy of Lusignan to advance and relieve the town.
Saladin commanded a large, well-supplied army with strong cavalry and horse-archers, and crucially held the wells and springs of the region. His discipline and control of water and terrain shaped the whole battle.
Guy of Lusignan led nearly the entire military strength of the kingdom — knights, sergeants, and infantry, including the Templars and Hospitallers. Committing this single army to a march through arid country was a gamble that left nothing in reserve if it failed.
As the crusaders marched toward Tiberias, Saladin's horsemen harassed the column and cut it off from water, forcing it to halt overnight in a waterless place. The next day, tormented by thirst and by fires the Muslims lit in the dry grass, the crusaders struggled toward the springs near the Horns of Hattin.
Saladin surrounded the army. The demoralised infantry broke away toward water and was cut to pieces, leaving the knights isolated. Despite desperate charges — Raymond III of Tripoli cut his way out with a few followers — the encircled and exhausted cavalry could not break Saladin's lines and was overwhelmed on the hillside.
Saladin captured King Guy of Lusignan, most of the surviving nobles, and the relic of the True Cross. He spared the king but executed Reynald of Châtillon with his own hand and had the captured Templars and Hospitallers put to death as irreconcilable enemies.
With the kingdom's army destroyed, its fortresses and towns fell in quick succession, and Jerusalem surrendered to Saladin in October 1187 after negotiation with Balian of Ibelin. The loss of the holy city stunned Latin Christendom and prompted the launching of the Third Crusade.
Hattin was the decisive battle of Saladin's career and the greatest disaster ever suffered by the crusader states, reducing the Kingdom of Jerusalem in weeks from a functioning realm to a few coastal enclaves.
It is a classic study of a commander using thirst, terrain, and control of water to destroy a stronger-looking enemy, and its consequence — the fall of Jerusalem — reshaped the crusading movement for the next century.