Complex sentence: When the prince of Achaea, Prince William II Villehardouin was defeated and captured at the Battle of Pelagonia as well as Baron Jean de Neuilly II the barony passed to his daughter Margaret de Passavas, widow of the Lord of Lisarea Guibert de Cors.
Split into simpler sentences: When the prince of Achaea, Prince William II Villehardouin was defeated and captured at the Battle of Pelagonia, the Baron Jean de Neuilly II was captured as well. Then, the barony passed to his daughter Margaret de Passavas, widow of the Lord of Lisarea Guibert de Cors.