 Complete the following phrase:  Wasif was originally a slave ghulam and was owned by the Numan family in Baghdad, where he worked as an armorer. At some point he was purchased by the future caliph al-Mutasim r. 833842, and he soon rose to prominence as a member of the Abbasids new Turkish corps. When al-Mutasim decided to move his capital to Samarra in 836, Wasif and his followers were settled in the new city, having received land allotments adjacent to al-Hayr. In 838 Wasif participated in al-Mutasims 