own only as long as they received a constant supply of fresh recruits from home and the forces of opposition were not unified under strong leadership.
Their early good fortune in finding Syria divided among weak and mutually hostile amirs — some eager to appease the Franks and have them as allies — could not last in- definitely, but it did last for several decades. When Duqaq of Damascus died (1104), his young son's regent Tughtigin usurped power and passed it on after his death to his sons, who kept Damascus independent until 1154 by alternately fighting the Franks and making alliances with them. Rid- wan's heirs at Aleppo were incompetent, and in 1117 the town passed into the hands of Il-Ghazi, a Turkoman who ruled Mardin. He was a redoubtable warrior against the Crusaders, but could never secure sufficient Moslem aid to do permanent damage.
In 1128 Aleppo was annexed by another warlike Turk, Imad-al-Din Zengi of Mosul. In subsequent years Zengi added Hamah, Horns and Baalbek to his realm, and in 1144 he wrested Edessa from the Franks. Its fall marks the beginning of the turn of the tide in favour of Islam. On the European side it provoked the so-called second Crusade (1147-1149). The usual classification of the Crusades, how- ever, into a fixed number of campaigns is artificial, as the stream was somewhat continuous and the line of demar- cation not sharply drawn. A more satisfactory division would be into first a period of Latin conquest extending to 1144; second a period of Moslem reaction inaugurated by Zengi and culminating in the brilliant victories of Saladin; and third a period of petty wars, coinciding roughly with the thirteenth century, in which the Ayyubids and the Mamluks figured and which ended in driving all Crusaders out of the land.
At Zengi's death (1146) the task of advancing the Islamic cause passed to his son Nur-al-Din Mahmud. The Crusade, led by Louis VII of France and Conrad III of Germany,
