While Hassan abode in Egypt the question of the succession to the throne (always a matter of dispute in Oriental monarchies) became a subject of dissension and angry debate at court. The khalif had declared his eldest son, Nesar, to be his legitimate successor; but Bedr-al-Jemali, the Emir-al-Juyoosh, or commander-in-chief of the army, who enjoyed almost unlimited power under the Fatimites, asserted the superior right of Musteäli, the khalif's second son, which right his power afterwards made good. Hassan Sabah, not very wisely, as it would seem, took the side of Prince Nesar, and thereby drew on himself the hostility of Bedr-al-Jemali, who resolved on his destruction. In vain the reluctant khalif struggled against the might of the powerful Emir-al-Juyoosh; he was obliged to surrender Hassan to his vengeance, and to issue an order for committing him to close custody in the castle of Damietta. While Hassan lay in confinement at Damietta one of the towers of that city fell down without any apparent cause. This being looked upon in the light of a miracle by the partisans of Hassan and the khalif, his enemies, to prevent his deriving any advantage from it, hurried him on board of a ship which was on the point of sailing for Africa. Scarcely had the vessel put to sea when a violent tempest came on. The sea rolled mountains high, the thunder roared, and the lightning flamed. Terror laid hold on all who were aboard, save Hassan Sabah, who looked calm and undisturbed on the commotion of the elements, while others gazed with agony on the prospect of instant death. On being asked the cause of his tranquillity he made answer, in imitation probably of St. Paul, "Our Lord (_Seydna_) has promised me that no evil shall befall me." Shortly afterwards the storm fell and the sea grew calm. The crew and passengers now regarded him as a man under the especial favour of Heaven, and when a strong west wind sprung up, and drove them to the coast of Syria, they offered no opposition to his leaving the vessel and going on shore.