Venerable Nikon, Abbot of Radonezh, disciple and successor of Saint Sergius.
Venerable Nikon came as a young man to Saint Sergius of Radonezh and became his closest disciple, succeeding him as abbot of the Holy Trinity monastery. After the monastery was burned by the Tatars he rebuilt it and had the relics of Saint Sergius uncovered.
He commissioned Andrei Rublev to paint the famous icon of the Holy Trinity, and reposed in 1426.
Feast day
On the New Calendar, Nikon of Radonezh is commemorated on November 17. Churches on the Old (Julian) Calendar keep the feast on November 30 of the civil calendar.
Also commemorated on November 17

Gregory the Wonderworker
Hierarch, Γρηγόριος Θαυματουργός
Bishop Gregory the Wonderworker of Neocaesarea.
Gennadios and Maximos of Constantinople
Hierarch, Γεννάδιος και Μάξιμος Πατριάρχες
Saints Gennadios I and Maximos III, Patriarchs of Constantinople.
Lazarus the Iconographer
Venerable, Λάζαρος ο Ζωγράφος
Venerable Lazarus the Iconographer of Constantinople, confessor under the iconoclasts.
Zacharias the Shoemaker and John
Saint, Ζαχαρίας ο Σκυτοτόμος και Ιωάννης
Righteous Zacharias the Shoemaker and John, who lived hidden lives of virtue in Constantinople.
Gennadios of Vatopedi
Venerable, Γεννάδιος ο Βατοπαιδινός
Venerable Gennadios of Vatopedi, steward of the monastery, witness of the miracle of the oil.