As early as the third (Lardner's.Credibility of the Gospel, part ii. vol. iii. p. 89-92), or at least the fourth century (Carol. a Sancto Paulo, Notit. Eccles. p. 47), the Port of Rome was an episcopal city, which was demolished, as it should seem, in the ninth century, by pope Gregory IV., during the incursions of the Arabs. It is now reduced to an inn, a church, and the house or palace of the bishop, who ranks as one of six cardinal bishops of the Roman church. See Eschinard, Descrizione di Roma et dell' Agro Romano, p. 328.