Complex sentence: The miniature "Thorne Rooms", each with a different theme, were designed by Mrs. James Ward Thorne and furniture for them was created by craftsmen in the 1930s and 40s.
Split into simpler sentences: The miniature "Thorne Rooms", each with a different theme, were designed by Mrs. James Ward Thorne. She commissioned furniture for them from craftsmen in the 1930s and 40s.