 Complete the following phrase:  Ahmad was the son of al-Khasib ibn Abd al-Hamid, a fice officer in Egypt during the reign of Harun al-Rashid r. 786809. Early in Ahmads career, he entered the service of the Turkic general Ashinas, becoming the latters secretary katib. In 838 he is mentioned as assisting Ashinas in thwarting a plot by several military officers to assassinate the caliph al-Mutasim r. 833842 during the 