Complex sentence: Little information exists about the interiors from the medieval and Baroque eras, but the palace built at the turn of the 20th century was meticulously recorded, using detailed descriptions, photographic documentation, and grounds plans.
Split into simpler sentences: Little information exists about the interiors from the medieval and Baroque eras. However, the palace built at the turn of the 20th century was meticulously recorded, with detailed descriptions, photographic documentation, and grounds plans.