In the Eastern church the Nicene creed is used instead. The Song of the angelic host is the ground-work of the Gloria in Excelsis. Tlie Apocalypse is one sublime liturgic A^sion. With these belong also the Psalms, which have passed as a legitimate inheritance to the Christian church, and have afforded at all times the richest material for public edification. In the ante-Nicene age we find as yet no traces of liturgical books. In each church, of course, a fixed order of worship gradually formed itself, which in apostolic congregations ran back to a more or less apostolic origin, but became enlarged Christ; Acts xiil. 2; Rom. xv. 16; Rom. rv. 2Y; 2 Cor. ix. 12, where rehgious fasting, missionary service, and common beneficences are called Xenovpyia. or Aej- TovpyeTv. The restriction of the word to divine worship or sacerdotal action occurs as early as Eusebius, Vita Const, iv. 37, bishops being there called KurovpyoL The limitation of the word to the service of the Lord's Supper is connected with the development of the doctrine of the eucharistic sacrifice. 520 THIRD PEEIOD. A.D. 311-590. and altered in time, and, until the fourth centmy, was per- petuated only by oral tradition. For the celebration of the sacraments, especially of the Eucharist, belonged to the Disci- plina arcani, and was concealed, as the most holy thing of the church, from the gaze of Jews and heathens, and even of catechumens, for fear of profanation ; through a misunderstand- ing of the warning of the Lord against casting pearls before swine, and after the example of the Samothracian and Eleusin- ian mysteries.' On the downfall of lieathenism in the Roman empire the Disciplina arcani gradually disappeared, and the administration of the sacraments became a public act, open to all. Hence also we now find, from the fourth and fifth centuries onward, a great number of written liturgies, and that not only in the orthodox catholic church, but also among the schismatics (as among the ]^estorians, and the Monophysites). These litur- gies bear in most cases apostolic names, but in their present form can no more be of apostolic origin than the so-called Apostolic Constitutions and Canons, nor nearly so much as the Apostles' Creed. They contrast too strongly with the simplici- ty of the original Christian worship, so far as we can infer it from the New Testament and from the writings of the apolo- gists and the ante-l^icenc fathers. They contain also theological terms, such as o^oovo-lo'^ (concerning the Son of God), SeoTo/co9 (concerning the Virgin Mary), and some of them the whole Ni- cene Creed with the additions of the second oecumenical council of 381, also allusions to the worship of martyrs and saints, and to monasticism, which point unmistakably to the Nicene and post-Nicene age. Yet they are based on a common liturgical tradition, which in its essential elements reaches back to an earlier time, perhaps in some points to the apostolic age, or even comes down from the Jewish