Complex sentence: The main characters in the book are given pseudonyms from Margaret Mitchell's "Gone with the Wind" (1936), but some of them have been identified, among them Cardinal Achille Silvestrini, Martinelli's former boss.
Split into simpler sentences: The main characters in the book are given pseudonyms from Margaret Mitchell's "Gone with the Wind" (1936). However, some of them have been identified, among them Cardinal Achille Silvestrini, Martinelli's former boss.