Complex sentence: Ar-Rashid appointed Ali bin Isa bin Mahan as the governor of Khorasan, who tried to bring to heel the princes and chieftains of the region, and to reimpose the full authority of the central government on them.
Split into simpler sentences: Ar-Rashid appointed Ali bin Isa bin Mahan as the governor of Khorasan. He tried to bring to heel the princes and chieftains of the region, and to reimpose the full authority of the central government on them.