Complex sentence: After attempts to take the city by storm or subterfuge failed, the Byzantines established a ring of fortresses on the hills around the plain of Melitene, and methodically ravaged the area.
Split into simpler sentences: After attempts to take the city by storm or subterfuge failed, the Byzantines settled for a blockade of the city. They established a ring of fortresses on the hills around the plain of Melitene, and proceeded to methodically ravage the area.