ʿAbd al-ʿAzīz b. Marwān (d. 86/705), brother of the famed state-building caliph, ʿAbd al-Malik b. Marwān (d. 86/705), reigned as the amīr of Egypt and heir apparent to the Umayyad caliphate for over twenty years. ʿAbd al-ʿAzīz, however, died just a few months before his brother ʿAbd al-Malik, and thus never ascended to the caliphate. The combination of his early death, the limited treatment of Egypt in the early Arabic historical sources, and the illustrious history of ʿAbd al-Malik have left ʿAbd al-ʿAzīz a largely unknown figure in western scholarship. This study seeks to revive the career of this largely forgotten amīr and demonstrate the critical role he played in the formation of the Marwānid dynasty, as well as the great autonomy he exercised within Egypt.