Complex sentence: The following year Elwes showed a portrait at the Royal Academy of Arts of Lady Lettice Lygon, the first of many noble sitters that would include many of Britain's Royal Family.
Split into simpler sentences: The following year Elwes showed a portrait at the Royal Academy of Arts of Lady Lettice Lygon. She was the first of his many noble sitters that would include many of Britain's Royal Family.