Complex sentence: William successfully held the castle and was made the Earl of Somerset by the grateful Empress, although chroniclers complained of the way in which he subsequently raided and controlled the region through force during the war, causing much destruction.
Split into simpler sentences: William successfully held the castle and was made the Earl of Somerset by the grateful Empress. Chroniclers subsequently complained of the way in which he subsequently raided and controlled the region through force during the war, causing much destruction.