Gregory was a real Renaissance man born about 600 years before the Renaissance. From a holy family he became a monk early and spent most of his life teaching theology in that monastery (a monastery which, incidentally, lasted until the Armenian Genocide of the 20th century). A prolific theologian and writer, he is well recognized in the East, especially the Armenian Apostolic Church. In the West he has an "equipollent canonization" (basically recognizing his canonization by the East in the West without all the rigamarole) and proclaimed a Doctor of the Universal Church on 12 April 2015 by Pope Francis, making him one of the newest Doctors in the Church.
The thing is, the Armenian Apostolic Church rejected the doctrines of the Council of Chalcedon. So how is that a Church that rejected Chalcedon ("confess Chalcedon or take a beatin'!") can produce a Doctor of the Universal Church?
The Council of Florence in 1439 contains a bull of reunion with these Armenians, and Pope Benedict XIV in the 1700's saw those bulls as having merit and effect, regardless of the ups and downs in the relationship. John Paul II produced a common declaration (recognizing their liturgy and liturgical calendar among other doctrinal issues and things) with the head of the Armenian Apostolic Church in the 1990's and in fact uses Gregory as an example in his encyclical Redemptoris Mater, and allowed a reference to him in The Catechism of the Catholic Church (§2678).
That "they may all be one, as you, Father, are in me and I in you" Christ prays. Let us pray it with him!
Extra shout out to Baldomerus of Saint Justus, a blacksmith recognized for his selfless love and holiness, who became a monk late in life at the Monastery of St. Justus.
Now what prayers in this book may be pleasing to you,
what acceptable smoke of incense shall I offer to you,
O Christ, praised heavenly King,
if I do not pray to you to bless those whom I cursed,
tend to those I have bruised,
care for those I have alienated,
give refuge to those I have betrayed,
And heal the souls of those I have wounded in body?
-- From his Book of Lamentation