Liturgical Development

In the 4th century, the Eucharistic prayers of the two most prominent liturgies of the Eastern Church—the Divine Liturgy of Saint Basil the Great, and the Divine Liturgy of Saint John Chrysostom, Archbishop of Constantinople (d. 407)—were substantially formulated. The catechetical sermons of Saint John Chrysostom, together with those of Saint Cyril, Bishop of Jerusalem (d. 386), show that the sacraments of Baptism and Chrismation were being celebrated in the fourth century almost exactly as they are done in the Orthodox Church today.

By this time, the 40-Day Great Lent and the Feast of Pascha (Easter) were well established. And the Feast of the Nativity of Christ (Christmas) was separated from the Feast of Theophany (Epiphany), thus becoming a separate feast of the Church (see Worship).