^The notation Old Style or (OS) is sometimes used to indicate a date in the Julian Calendar (which is used by churches on the "Old Calendar"). The notation New Style or (NS), indicates a date in the Revised Julian calendar (which is used by churches on the "New Calendar").
^The traditional Orthodox greeting, used from today until the Eve of Theophany, is: "Christ is Born!" And the response is, "Glorify Him!"[4]
^"[Roman and all Western Martyrologies. Also the Eastern Menaeas. The Carthaginian Kalendar of the 5th cent., and the ancient Roman Kalendar of the middle of the 4th cent., published by Bucherius.]"
"TILL the year 325 we have only uncertain traces of the observance of this festival; but in the middle of the fourth century, under Pope Liberius, we hear of it as generally observed in the Roman Church, and throughout the West. The celebration of the Feast of the Nativity spread from the West to the East, and S. John Chrysostom used his utmost endeavour to promote this introduction. Already, in 386, S. John Chrysostom says that the festival was observed in Antioch. The festival is ordered to be observed with reverence and dignity by the councils of Agde in 504 (can. 64), of Orleans in 511 (can. 24), and of Epaone in 517 (can. 35). Before this, the commemoration of the Nativity was united with that of the Epiphany, which is far the more ancient festival of the two... ... ...On December 25th the Greeks also commemorate the Adoration of the Magi."[6]
^A virgin-martyr in Rome under Valerian, she was buried in the cemetery of Apronian on the Via Latina.
^According to her Life, she suffered in Sirmium in Dalmatia, her relics were taken to Constantinople and veneration spread to Rome, where a basilica is dedicated to her.
^See: (in Russian)Иона Печенгский. Википедии. (Russian Wikipedia).
^This raid was carried out by a Finnish peasant chief named Pekka Antinpoika Vesainen, on December 25, 1589, and was part of the Russo-Swedish War (1590–1595).
^The Autonomous Orthodox Metropolia of Western Europe and the Americas (ROCOR). St. Hilarion Calendar of Saints for the year of our Lord 2004. St. Hilarion Press (Austin, TX). p.2.
^The Roman Martyrology. Transl. by the Archbishop of Baltimore. Last Edition, According to the Copy Printed at Rome in 1914. Revised Edition, with the Imprimatur of His Eminence Cardinal Gibbons. Baltimore: John Murphy Company, 1916. pp.395-396.
The Autonomous Orthodox Metropolia of Western Europe and the Americas (ROCOR). St. Hilarion Calendar of Saints for the year of our Lord 2004. St. Hilarion Press (Austin, TX). p. 2.
December 25. Latin Saints of the Orthodox Patriarchate of Rome.
The Roman Martyrology. Transl. by the Archbishop of Baltimore. Last Edition, According to the Copy Printed at Rome in 1914. Revised Edition, with the Imprimatur of His Eminence Cardinal Gibbons. Baltimore: John Murphy Company, 1916. pp. 395–397.
(in Greek) Συναξαριστής. 25 Δεκεμβρίου. ECCLESIA.GR. (H ΕΚΚΛΗΣΙΑ ΤΗΣ ΕΛΛΑΔΟΣ).
Russian Sources
(in Russian)7 января (25 декабря). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia - Pravenc.ru).