Complex sentence: Her mother, Raissa Myshetskaya (Mischetzky), was a Russian princess who married her Paris Conservatoire teacher, Ernest Boulanger; grandfather Frédéric Boulanger had been a noted cellist, and grandmother Juliette a singer.
Split into simpler sentences: Her mother, Raissa Myshetskaya (Mischetzky), was a Russian princess who married her Paris Conservatoire teacher, Ernest Boulanger. Her grandfather Frédéric Boulanger had been a noted cellist and her grandmother Juliette a singer.