 By May he had defeated Sebük-eri on the field and released his son from captivity, and the conquest of Fars proceeded in earnest.Sebük-eri, however, was a caliphal vassal and received support from the Abbasids.Al-Layth's representative in Fars was defeated by Abbasid forces under Mu'nis al-Khadim in August, forcing al-Layth to come to terms, and he left Fars for Kerman.