Ramba uchiverenga ndima ino - Achiri pachinzvimbo ichi, muna Chikunguru-Nyamavhuvhu 803, Qasim akatungamirira kurwisa muByzantine Asia Minor. Akakomba nhare yeKoron, apo mutevedzeri wake al-'Abbas ibn Ja'far ibn Muhammad ibn al-Ash'ath akatumwa kukomba imwe nhare, yaizivikanwa nemaArabu seSinan. Zvisinei, vaByzantium vakati vaizosunungura vasungwa 320 vechiMuslim kana akabva, uye akabvuma. Muna Kukadzi 808, apo Harun akasiya imba yake Raqqa kuti aende kuKhurasan kechipiri, akasiya Qasim kumashure semutevedzeri wake muRaqqa, naKhuzayma ibn Khazim semupi wake wezano. Mushure mekufa kwaHaruni uye kutora chigaro chaal-Amin muna 809, Qasim akasimbiswa pachinzvimbo chake semubati we "al-'Awasim" uye we "jund Qinnasrin", asi sezviri pachena akabviswa pahutongi hwake hweJazira (Upper Mesopotamia), uko Khuzayma ibn Khazim akagadzwa pachinzvimbo. Pakupedzisira, muna 810, Qasim akabviswa naAmin kubva pahutongi hwake hwese achitsigira Khuzayma, ndokuunzwa kuti agare pasi pekutarisirwa zvakanyanya muBaghdad. Amin achangobva kurambidza kutaurwa kwake muminamato, pamwe naAbdallah al-Ma'mun, uyo akanga amuka mukumukira kweKhurasan. Muhondo yevagari vemo
pashure pacho, Ma'mun akakunda, achikunda nokuuraya munun'una wake Amin muna 813. Nokukurumidza pashure pacho, Qasim akabviswa pachinzvimbo chake semutsivi.