 From 1878 until his death, he served as Protector of the Pontifical North American College in Rome.Simeoni was named Prefect of the Sacred Congregation for the Propagation of the Faith, also known as the "Red Pope", on March 5, 1878, and president of the missionary seminaries of Rome on January 1, 1885.From March 27, 1885 to January 15, 1886, he served as Camerlengo of the Sacred College of Cardinals.