 From perhaps as early as the 3rd century, it has been used to denote a bishop, not exclusively the bishop of Rome.The name given to the book containing the liturgical rites to be performed by any bishop, "The Roman Pontifical", and to the form of liturgy known as Pontifical High Mass witness to the continued use of "pontifex" in this wide sense.In Emperor Theodosius's edict "De fide catholica" of 27 February 380, enacted in Thessalonica and published in Constantinople for the whole empire, by which he established Catholic Christianity as the official religion of the empire, he referred to the western Bishop of Rome, Damasus, as a "pontifex", while calling the eastern Bishop of Alexandria, Peter, an "episcopus"