Complex sentence: The next year, when James Francis Edward was expelled and Louise Mary died of smallpox, Mary was very upset; according to Mary's close friend Madame de Maintenon, Mary was "a model of desolation".
Split into simpler sentences: The next year, when James Francis Edward was expelled and Louise Mary died of smallpox, Mary very upset. According to Mary's close friend Madame de Maintenon, Mary was "a model of desolation".