Complex sentence: While it is clear that the First Emperor gathered and destroyed many works which he regarded as subversive, two copies of each were to be preserved in imperial libraries, which were destroyed in the fighting following the fall of the dynasty.
Split into simpler sentences: While it is clear that the First Emperor gathered and destroyed many works which he regarded as subversive, two copies of each were to be preserved in imperial libraries. These were destroyed in the fighting following the fall of the dynasty.