St. Hilary, Bishop of Poitiers, defender of the Nicene faith in the West.
St. Hilary was Bishop of Poitiers in Gaul in the fourth century. A convert from paganism, he became the foremost defender of the divinity of Christ in the West, was exiled to Asia Minor by the Arian emperor Constantius, and there wrote his treatise on the Holy Trinity.
He returned to his see and reposed in peace. He is commemorated on January 13.
Feast day
On the New Calendar, Hilary of Poitiers is commemorated on January 13. Churches on the Old (Julian) Calendar keep the feast on January 26 of the civil calendar.
Also commemorated on January 13

Stratonikos the Martyr
Martyr, Στρατόνικος
Holy Martyr Stratonikos, who suffered with St. Hermylos at Singidunum.
Name days: Stratonikos, Stratonicus
Maximos Kavsokalyvites
Venerable, Μάξιμος ο Καυσοκαλύβης
Venerable Maximos the Hut-Burner of Mount Athos.
James of Nisibis
Hierarch, Ιάκωβος Νισίβεως
St. James, Bishop of Nisibis, father of the Council of Nicaea.
Jeremiah I of Constantinople
Hierarch, Ιερεμίας Α΄
St. Jeremiah I, Patriarch of Constantinople in the sixteenth century.