The repose which Soliman had promised himself did not last long; the interruption came whence it was least expected. Of his numerous sons Mustapha, his eldest, was the child of a Circassian, whilst several others were children of Roxelana, a jealous and ambitious woman. The sister of this latter woman, married to the Grand Vizier Rustem, was the link by which she succeeded in obtaining his co-operation in her schemes. Seeing every probability of Mustapha eventually obtaining the throne to the exclusion of her own sons, Roxelana determined upon his death. Conspiring with Rustem, she forged letters purporting to be addressed by the heir-apparent to a friend of his, informing him that he was treating with his father's foe, the King of Persia, with the view of obtaining one of his daughters in marriage. At the same time that this communication was adroitly placed before Soliman, he received intelligence from his Grand Vizier that Prince Mustapha displayed a disposition to revolt, and was attending complacently to the seditious propositions of the emissaries. This startling news aroused the old hero; he immediately quitted his palace and its pleasures, placed himself once more at the head of his army, and summoned his son to his presence. On the 21st September, 1555, ignorant of the charges against him, or relying upon his innocence, the Prince arrived at his father's camp, was met by the chief captains, and conducted with all the pomp due to his rank as heir-apparent to an audience of the Sultan. On entering the imperial tent, the unfortunate man was seized by seven mutes, and strangled with a bowstring, calling vainly upon his father, who, hidden by a silken curtain, witnessed the horrible deed. Not satisfied with his son's death, the old monarch also caused his grandson Murat, Mustapha's child, to be put to death in the same way as its parent. Prince Ziangir, a younger brother of the assassinated man, was so distressed at the catastrophe, that, after reproaching his unnatural father, he committed suicide. The two princes were interred together, and a mosque erected over their remains. The army deeply deplored the loss of the unfortunate Mustapha, who was held in great esteem, and attributing his death to the schemes of Rustem clamoured for his dismissal. Yielding to the universal indignation, Soliman consented to deprive the Grand Vizier of his post, which was bestowed on Ahmed Pacha. The general feeling of grief which the heir-apparent's death caused throughout the empire found expression in numerous poems and elegies; and amongst others Yahïa, a celebrated contemporary poet, composed verses that were known and repeated in all parts of the empire. Two years later, when Rustem returned to power, he was desirous of having Yahïa executed, but this the Sultan would not consent to; and the Grand Vizier had to satisfy his vengeance with depriving the poet of his post of Administrator of Charity to the crown.