Baldwin III finally seized Ascalon in 1153, which brought Egypt into the sphere of conflict. Jerusalem was able to make further advances into Egypt, briefly occupying Cairo in the 1160s. However, relations with the Byzantine Empire were mixed, and reinforcements from Europe were sparse after the disaster of the Second Crusade. King Amalric I of Jerusalem allied with the Byzantines and participated in a combined invasion of Egypt in 1169, but the expedition ultimately failed. In 1171, Saladin, nephew of one of Nur ad-Din's generals, was proclaimed Sultan of Egypt, uniting Egypt and Syria and completely surrounding the crusader kingdom. Meanwhile, the Byzantine alliance ended with the death of emperor Manuel I in 1180, and in 1187, Jerusalem capitulated to Saladin. His forces then spread north to capture all but the capital cities of the Crusader States, precipitating the Third Crusade.