Complex sentence: The Palazzo is most often referred to by Romans simply as the "Palazzo Muti" or the "Palazzo Balestra", the Balestra being a family who lived in the palazzo for a time.
Split into simpler sentences: The Palazzo is most often referred to by Romans simply as the "Palazzo Muti" or the "Palazzo Balestra". The Balestra being a family who lived in the palazzo for a time.