Complex sentence: The French arrested him in his office at the Quirinal Palace in Rome and deported him to France in 1808, during the reign of Pius VII. He later returned to Rome where he served as prefect of the Sacred Congregation of the Council from 1814 to 1820.
Split into simpler sentences: The French arrested him in his office at the Quirinal Palace in Rome and deported him to France in 1808, during the reign of Pius VII, and later returned to Rome. He served as prefect of the Sacred Congregation of the Council from 1814 to 1820.