The rise and early victories of Saladin.
The Battle of Hattin took place on 4 July 1187, between the Crusader states of the Levant and the forces of the Ayyubid sultan Salah ad-Din, known in the West as Saladin. It is also known as the Battle of the Horns of Hattin, from a nearby extinct volcano.
The Muslim armies under Saladin captured or killed the vast majority of the Crusader forces, removing their capability to wage war. As a direct result of the battle, Muslims once again became the eminent military power in the Holy Land, re-conquering Jerusalem and most of the other Crusader-held cities.
These Christian defeats prompted the Third Crusade, which began two years after the Battle of Hattin.