representatives of the Apostles, Ignatius of Antioch sees the guarantee of the church’s unity. According to Cyprian, this unity has its expression in the Apostolate; in the Episcopate it has its support. The promise of Christ, Matt. xvi. 18, is given to Peter, not as the head but as the single representative of the Apostles (John xx. 21). The Apostolic office, with the promise attached to it, passed from the Apostles by means of ordination to the bishops. These, through their monarchical rank, represent continuously for the several churches (_Ecclesia est in episcopo_), and through their combined action, for the whole of Christendom, the unity of the church; _Episcopatus unus est, cujus a singulus in solidum, pars tenetur_. All the bishops, just as all the Apostles, have perfect parity with one another; _pares consortio, jure et honore_. Each of them is a successor of Peter and heir of the promise given first to Peter but for all.--He who cuts himself off from the bishops, cuts himself off from the church. _Habere non potest Deum patrem, qui ecclesiam non habet matrem.... Extra ecclesiam nulla spes salutis._ Alongside of the Apostolic writings, the tradition which prevailed among the Apostolic churches (_Sedes apostolicæ_) was regarded as a standard of catholicity in constitution, worship and doctrine; indeed, it must even have ranked above the Apostolic writings themselves in settling the question of the New Testament Canon (§ 36, 8), until these had secured general circulation and acceptance.