In 1164, King Amalric of Jerusalem invaded Fatimid Egypt, which requested help from Nur ad-Din. The Nur ad-Din sent his general Shirkuh, and in 1166 Amalric was defeated at the Battle of al-Babein. When Shirkuh died in 1169, he was succeeded by his nephew Yusuf, better known as Saladin, who defeated a joint crusader-Byzantine siege of Damietta. Saladin eventually overthrew the Fatimid caliphs and established himself as Sultan of Egypt. He also began to assert his independence from Nur ad-Din, and with the death of both Amalric and Nur ad-Din in 1174, he was well-placed to begin exerting control over Damascus and Nur ad-Din's other Syrian possessions. In 1177 Saladin was defeated by the crusaders at the Battle of Montgisard, despite his numerical superiority. Saladin also besieged Kerak in 1183, but was forced to withdraw. He finally launched a full invasion of Jerusalem in 1187, and annihilated the crusader army at the Battle of Hattin in July. Acre fell to Saladin soon after, and Jerusalem itself was captured in October. These events shocked Europe, resulting in the Third Crusade in 1189, led by Richard I of England, Philip II of France and Frederick I, Holy Roman Emperor, though the last drowned en route.