Complex sentence: Her sister Constance Gosselin was the wife of the dancer Auguste-Anatole Petit; another sister, Louis Gosselin, was a premier dancer in London and Paris and her other sister, Henriette Gosselin, danced with the Paris Opera from 1821-1830.
Split into simpler sentences: Her sister Constance Gosselin was the wife of the dancer Auguste-Anatole Petit. Another sister, Louis Gosselin, was a premier dancer in London and Paris and her other sister, Henriette Gosselin, danced with the Paris Opera from 1821-1830.