Original sentence: He had a privileged childhood in Rome, where he was brought up Catholic in a loving but argumentative family, who imagined themselves to be the legitimate heirs to the thrones of England, Scotland, and Ireland (according to the hypothetical and propagandist Jacobite succession) and staunchly believed in the divine right of kings
Edited sentence: He had a privileged childhood in Rome, where he was brought up Catholic in a loving but argumentative family, who imagined themselves to be the legitimate heirs to the thrones of England, Scotland, and Ireland (according to the mythical Jacobite succession) and staunchly believed in the divine right of kings