The Umayyad Caliphate during the reign of Hisham b. 'Abd al-Malik (105-125/724-743) is the theme of this study. It commences with a survey of the major sources and brief comments on some relevant modem works. Chapter I deals with the early life of Hisham and the situation in the empire prior to his accession to the throne. The second Chapter is concerned with the Shi'i opposition and is divided into two parts: part I deals with the revolt of Zayd b. 'Ali. In it Zayd's relationship with his brother, al-Baqir, and his son, Ja'far al-Sadiq, and also with Wasil b. 'Aia' are discussed. Zayd's activities before his revolt in addition to the events of the rebellion and its consequences are thoroughly investigated. Part II deals with the ghulat movement during the period under study. Chapter III is also divided into two parts: part I deals with the Berber revolt in North-Africa. The motives, events and the results of this rebellion are discussed. The Civil War in Spain is the subject of part II. The Kharijite opposition in the east and the Coptic revolts in Egypt are presented in the fourth Chapter. The motives, events and results of the rebellious movement of al-Harith b. Surayj are scrutinised in the fifth Chapter. The sixth Chapter deals with the Arab conquest in Khurasan and Transoxania while the seventh Chapter is concerned with the Arab conquest in Armenia, Adharbayjan and Caucasus in addition to the Arab-Khazar war during the period under consideration.