Complex sentence: He and his wife, Mary Carling (née Dunlop) "Mollie" McCrea, originally of Petersburg, had the mansion substantially modernized and expanded under the guidance of Richmond architect Duncan Lee.
Split into simpler sentences: He and his wife, Mary Carling (née Dunlop) "Mollie" McCrea originally of Petersburg. The McCreas had the mansion substantially modernized and expanded under the guidance of Richmond architect Duncan Lee.