Nyorera kupfuurira kweiyi ndima - Fadl akatanga basa rake mukutonga kwaHarun al-Rashid (r. 786<unk>809) semushandi waHarthama ibn A'yan, panguva iyoyo mukuru wevarindi vemucaliphal. Tarenda rake rokutarisira zvinhu rakaita kuti aonekwe naHarun, uyo akamugadza kuva munyori mu"diwan al-kharaj" ("Bureau of the Land Tax"). Munguva yehondo yevagari vemo
pashure porufu rwaHarun, Fadl akaenda kunzvimbo yake muIraq. Ikoko ndiko kwaakazozivikanwa naAbu Ishaq, munun'una waCaliph al-Ma'mun (r. 813<unk>833) uye Caliph al-Mu'tasim, uyo aikoshesa ruzivo rwake rwemutero nezvekurima. Muna 828, Abu Ishaq akaenda naye kuEgypt ndokumugadza kuti atungamirire "diwan al-kharaj".