1175 the Abbasid caliph at Saladin's request granted him a diploma of investiture over all these lands, thereby giving away what in reality was not his to give but what it was flattering to him not to refuse. The incorporation of upper Mesopotamia (except Mosul) rounded out the sultanate. Nur-al-Din's dream of enveloping the Franks and crushing them to death was becoming a reality through the achieve- ments of his more illustrious successor.
At last Saladin was free to concentrate on 'the infidels'. The hour of peril for the Latin kingdom struck when, after a six-day siege, Tiberias fell and the Moslem army moved to cut off the Frankish forces under the stubborn and incom- petent king of Jerusalem, Guy of Lusignan, at Hattin, over- looking the Sea of Galilee. There the battle was joined July 3 to 4, 1187. The heat was intense. Exhausted from the long march and crazed with thirst, the heavily armoured Franks were surrounded by lightly armoured Moslems and subjected to an incessant shower of arrows. Of the 20,000 knights and infantry only a few escaped; the rest were slaughtered or captured. Prominent among the captives was Guy of Lusignan, who was received as befitted his rank by the magnanimous and chivalrous sultan.
The destruction on the day of Hattin of the Frankish army, which comprised besides the capital's garrison con- tingents from the other states, sealed the fate of the Latin kingdom. After a week's siege Jerusalem capitulated on October 2. Saladin's treatment of the Frankish populace stood in sharp contrast to the treatment accorded the Moslems eighty-eight years earlier. Those who could ransom themselves individually did so; the poor were allowed forty days to collect a lump sum for ransom and the rest were sold as slaves. The lands of the evacuated Franks were purchased by troops and native Christians. From Jerusalem the tide of conquest continued, engulfing all the Frankish holdings except Tyre, Tripoli, Antioch and a few castles.
