Gregory of Nazianzus
The Eastern Orthodox Church honors many of the pre-schism saints as well, but the term "Doctor of the Church" is not applied in the same way. One consistent use of the category is the trio of Basil the Great, Gregory of Nazianzus and John Chrysostom, recognized as universal teachers and known as the Three Holy Hierarchs. The church also recognizes three saints with the title "Theologos" (Theologian): John the Evangelist, Gregory of Nazianzus and Symeon the New Theologian.