Complex sentence: He also restored and embellished the damaged Basilica di San Paolo fuori le Mura and St. Peter's: the latter's altar again received its gold covering (after being stolen), which weighed 206 lb. and was studded with precious gems.
Split into simpler sentences: He also restored and embellished the damaged Basilica di San Paolo fuori le Mura and St. Peter's. The latter's altar again received its gold covering (after being stolen), which weighed 206 lb. and was studded with precious gems.