Complex sentence: Only a few of the house's exceptional wooden decorative panels existed prior to the Syrian civil war as a number of pieces had already been lost, dismembered and sold to individuals or to museums.
Split into simpler sentences: Only a few of the house's exceptional wooden decorative panels were in place prior to the Syrian civil war. By the time of its restoration, a number of pieces had already been lost, dismembered and sold to individuals or to museums.