Complex sentence: It was then sacked by the Lombards in 558, and later by the Moors in 737, so Francia's king divided Frankish Burgundia into three parts in 843 by the Treaty of Verdun, hence Vienne became part of Middle Francia.
Split into simpler sentences: It was then sacked by the Lombards in 558, and later by the Moors in 737. When Francia's king divided Frankish Burgundia into three parts in 843 by the Treaty of Verdun, Vienne became part of Middle Francia.