Their ethnic composition is not discussed explicitly in the sources, but it appears that they were mostly of Khurasani Iranian origin, drawn from the troops that had fought for al-Ma'mun in the Fourth Fitna. In the list of cantonments of the regular regiments in Samarra a number of Khurasani commanders (quwwād) and their followers (aṣhāb) are mentioned as settled "in the jund and the shākiriyya", and in the few occasions where shākirī commanders are mentioned, their names denote a Khurasani origin. Hugh N. Kennedy suggested that these troops were raised by Tahir ibn Husayn for service in the west, and that the name was chosen as "a sort of honorific, referring back to a heroic and chivalrous past". Kennedy also suggested that remnants of the pre-civil war Abbasid army, the abnāʾ al-dawla, may have been incorporated in the jund and shākiriyya.
