The large-scale encroachment of the dependents on the territory of the service aristocracy began under Mahdī and Hārūn. Mahdī turned the clients of the ʻAbbāsid house into a servile army fighting under its own commanders and filled a substantial number of governorships with men of this kind; much resented by the Khurāsānīs, this policy was continued by his successors. Hārūn in addition recruited free clients among the non-Arabs of Khurāsān. The enrolment of foreigners was not without precedent. Already in 766[149] a Christian churchman had been scandalized by the ‘locust swarm’ of Alans, Khazars, Kufans, Ethiopians, Medians, Persians and Turks who went on summer campaign in that year, worshipping the sun and carrying with them the false gods of their nations. But the scale of Hārūn's enterprise was doubtless new. Altogether half a million Iranians are said to have been recruited, presumably on making a formal renunciation of their false gods, and like the locust swarm they became mawātī of the caliph. Graced with the name of ʻAbbāsiyya, some twenty thousand were transferred to Baghdad where, if the figures are at all correct, they were numerically on a par with the Abnāʼ. Though the freedmen and the Iranians were different types of clients, they were inspired by the same concern.