In tribal Middle Eastern, Arab, Persian, and Kurdish societies, a guest house of the tribal chieftain is used mostly for discussing tribal affairs. This served as an institution dedicated to the political and social affairs of the tribe. A diwan or diwan-khane, was a special room, or house, dedicated to the "agha" and his male guests, for sitting and drinking tea, discussing the political and social affairs of the tribe and other mundane subjects. The agha and his guests would also listen to singers and story tellers (usually Jewish merchants or peddlers), who would entertain them. The common agha was in charge of several major tasks of the tribal society under his jurisdiction: He was the head of the political unit, the judge and arbitrator, the military leader and the finance minister responsible mainly for receiving dues/taxes from his subjects for their harvest and commercial transactions under his jurisdiction. One of the best studies on aghas in the Kurdish society is the important book of Mordechai Zaken, Jewish subjects and their tribal chieftains in Kurdistan.
- Zaken, Mordechai (2007). Jewish Subjects and Their Tribal Chieftains in Kurdistan (Jewish Identities in a Changing World). BRILL. p. 376. ISBN 90-04-16190-2. Retrieved February 13, 2011.