Complex sentence: Joseph Rosati, C.M., was an (Italian-born) Catholic missionary in the United States who served as the first bishop of the Diocese of Saint Louis between 1826 and 1843.
Split into simpler sentences: Joseph Rosati, C.M., was an (Italian-born) Catholic missionary in the United States. He served as the first bishop of the Diocese of Saint Louis between 1826 and 1843.