The story of the annexation of Ziy͞ad b. Ubaydto Abii Sufyan is well known in the history of Islam. Probably this fame, more than its illegitimacy, is due to the fame of Ziy͞ad himself as one of four Arab sagacious men, and as one of three effective figures who assisted Mu͞awiya in strengthening the basis of Umawid Caliphate. Ziy͞ad's desire to be a Caliph, which was not accomplished, was only pledged to the acceptance of the annexation and relation to Mu͞awiya. After the recognition of annexation, he knew himself as Mu͞awiya's brother and a competitor of his crown prince, and craved for Caliphate. Therefore he didn't contribute in Yaz͞id's crown prince-ship and the hereditary of Caliphate. Though the annexation cost too much for Muslim society of Iraq, and disgraced Ziy͞ad himself, but made him and Mu͞awiya, even more than him, successful to achieve their desires. This paper is to investigate motivations and consequences of this subject from a historical point of view. (F.S.)