Constantine, the emperor Heraclius' son, guarded that part of the country where Amrou lay, with a considerable army. The weather was very cold, and the Christians were quite disheartened, having been frequently beaten and discouraged with the daily increasing power of the Saracens, so that a great many grew weary of the service and withdrew from the army. Constantine, having no hopes of victory, and fearing lest the Saracens should seize Caesarea, took the opportunity of a tempestuous night to move off, and left his camp to the Saracens. Amrou, acquainting Abu Obeidah with all that had happened, received express orders to march directly to Caesarea, where he promised to join him speedily, in order to go against Tripoli, Acre, and Tyre. A short time after this, Tripoli was surprised by the treachery of Youkinna, who succeeded in getting possession of it on a sudden, and without any noise. Within a few days of its capture there arrived in the harbor about fifty ships from Cyprus and Crete, with provisions and arms which were to go to Constantine. The officers, not knowing that Tripoli was fallen into the hands of new masters, made no scruple of landing there, where they were courteously received by Youkinna, who proffered the utmost of his service, and promised to go along with them, but immediately seized both them and their ships, and delivered the town into the hands of Kaled, who was just come. With these ships the traitor Youkinna sailed to Tyre, where he told the inhabitants that he had brought arms and provisions for Constantine's army; upon which he was kindly received, and, landing, he was liberally entertained with nine hundred of his men. But being betrayed by one of his own soldiers, he and his crew were seized and bound, receiving all the while such treatment from the soldiers as their villanous practices well deserved. In the mean time Yezid Ebn Abu Sofian, being detached by Abu Obeidah from the camp before Caesarea, came within sight of Tyre. The governor upon this caused Youkinna and his men to be conveyed to the castle, and there secured, and prepared for the defence of the town. Perceiving that Yezid had with him but two thousand men in all, he resolved to make a sally. In the mean time the rest of the inhabitants ran up to the walls to see the engagement. While they were fighting, Youkinna and his men were set at liberty by one Basil, of whom they give the following account, viz.: That this Basil going one day to pay a visit to Bahira the monk, the caravan of the Koreishites came by, with which were Kadija's camels, under the care of Mahomet. As he looked toward the caravan, he beheld Mahomet in the middle of it, and above him there was a cloud to keep him from the sun. Then the caravan having halted, as Mahomet leaned against an old, withered tree, it immediately brought forth leaves. Bahira, perceiving this, made an entertainment for the caravan, and invited them into the monastery. They all went, leaving