Complex sentence: Later renovations and restorations added elements in other styles, such as the Renaissance retablo at the high altar, destroyed in the 1755 Lisbon earthquake, and of which today fragments are housed in the church.
Split into simpler sentences: Later renovations and restorations added elements in other styles, such as the Renaissance retablo at the high altar. It was destroyed in the 1755 Lisbon earthquake and fragments of it are housed in the church.