Complex sentence: The Saint-Guilhem cloisters date to 804, Barnet, 58 from the site of the later Benedictine monastery of Saint-Guilhem-le-Désert, with other pieces dating to the 1660s.
Split into simpler sentences: The Saint-Guilhem cloisters originate from the site of the Benedictine monastery of Saint-Guilhem-le-Désert. Some elements date to 804, Barnet, 58 with other pieces from the 1660s.