The organisation of the Latin East was hardly completed when the period of decline set in. Much of the success of the First Crusade had been due to the antagonism of Turk and Arab, and the break-up of the Seljukian kingdom. In the generation following, a new danger arose in the growth of a consolidated Mohammedan state in Syria. Imad-ed-din Zangi was a Turk whose father had been a trusted follower of Malek Shah, and who, after a stormy youth, had been, in 1127, made governor, or Atabek, of Mosul. In the course of the next fifteen years Zangi destroyed all the rival Mohammedan powers in northern Syria and Mesopotamia, and then turned his arms against Edessa, the remote crusading county that encroached upon his territories and threatened his capital. Jocelin of Courtenay, who ruled Edessa after Baldwin became King of Jerusalem, opposed him by a vigorous resistance, but Jocelin’s son, Jocelin II., was a cowardly voluptuary, who left Edessa almost undefended. [Sidenote: Fall of Edessa, 1144.] In 1144 Zangi conquered Edessa, and put the Frankish garrison to the sword. The whole county was speedily overrun, and the Latin East experienced its first great disaster. [Sidenote: St. Bernard and the Second Crusade.] The fall of Edessa filled Europe with alarm, and St. Bernard, then in the plenitude of his influence, preached a new crusade with extraordinary fervour, and won over the two foremost princes in Christendom. Louis VII., King of France, had already taken the Crusader’s vow to expiate an early crime of violence [see page 284], but his barons, and his minister Suger, urgently dissuaded him. At Easter, 1146, St. Bernard appeared before a great gathering at Vézelai, and amidst scenes that recalled the first enthusiasm at Clermont, all ranks took the cross from the hands of the great Cistercian. After preaching the crusade over northern France, Bernard went to Germany, and at Christmas, in the cathedral at Speyer, overcame by his eloquence the hesitation of Conrad III. [Sidenote: Crusade of Conrad III.]