January 25 in Eastern Orthodox liturgical calendars is a feast day and a day of commemoration of saints and martyrs. Although some Orthodox churches use the Revised Julian Calendar and others use the traditional Julian calendar, the fixed commemorations for their respective January 25 are broadly the same, no matter which calendar is used.
Venerable Castinus, Bishop of Byzantium (240)
Martyr Medula and her entourage.
Venerable Apollo of the Thebaid, ascetic and wonderworker, reposed in peace (c. 361-363)
Saint Bretanion (Vetranion), Bishop of Tomis in Moesia, Confessor (c. 380)
Venerable Publius the Ascetic of Euphratensis, Syria (380)
Venerable Theodotos, Igumen of the "Monastery of St. Publius".
Saint Gregory the Theologian of Nazianzus, Archbishop of Constantinople (390)
Venerable Mares the Singer of Omeros near Cyrrhus, Syria (430)
Venerable Demetrius the Skeuophylax ("Keeper of the Sacred Vessels") of Constantinople (8th century)
Martyr Felicitas of Rome, and her seven sons (c. 164): (see also: November 23 - West)
Januarius, Felix, Philip, Silvanus, Alexander, Vitalis, and Martial.
Saint Artemas, a child martyr in Pozzuoli (Puteoli) in Italy.
Saint Dwynwen of Llanddwyn Island, Patroness of Love and Marriage (c. 460)
Saint Eochod of Galloway, Apostle of the Picts of Galloway (597)
Saint Maurus (584) and Saint Placidus (6th century), early disciples of Saint Benedict.
Saint Sigeberht of East Anglia (Sigebert), the first Christian King of East Anglia in England (634)
Saint Racho (Ragnobert), Bishop of Autun, France (c. 660)