Christianity changed considerably in the fourth century with the conversion of Constantine, who made Christianity legal and opened the door toward its accommodation with society. Worship developed rapidly through extensive building projects, the development of liturgies, the observance of the Christian year, creation of the lectionary, and the contributions of music and the arts. In this setting, preaching took on the characteristics of Roman rhetoric and became considerably more formal. Among the Greek Christians of the time, several stand out as exceptional preachers, especially Basil the Great, his brother Gregory of Nyssa, Gregory of Nazianzus—collectively called the Cappadocians—and John Chrysostom, who will be treated in the next entry.
The Greek Fathers were important champions and defenders of the Nicene Creed and their influence as men of God who would never waver in their faith did much to defend orthodoxy against heresy and the interference of the government.