May 12 (Eastern Orthodox liturgics)

• Saint Domitilla the martyr (c. 81-96)^[1][2]
• Saints Nereus and Achilleus the martyrs (100)^[2][3]
• Saint Dracontius, Bishop of Nicaea (c. 1st to 3rd centuries)^{[4][note 2]}
• Saint Epiphanius, Bishop of Salamis and Metropolitan of Cyprus (403)^[2][5]
• Saint Calliope (Callitropos), nun, sister of St. Epiphanius of Cyprus.^[6]
• Saint Sabinus, Archbishop of Cyprus (successor of St. Epiphanius to the Cypriot cathedra) (5th century)^[7][8]
• Saint Polybius, Bishop of Cyprus, Wonderworker (5th century)^[7][9]
• Saint Theophanes, Archbishop of Cyprus (7th century)^{[10][11][note 3]}
• Patriarch Germanus I of Constantinople (740)^[2][12]
• Venerable Theodore of Kythera, ascetic (922)^[13][14]

• Saint Philip of Agira the Hieromartyr (103)^{[2][15][note 4]}
• Martyr Pancratius of Rome (304)^[2][16][17]
• Martyr Dionysius (Denis), uncle of St. Pancratius (304)^[2][18]
• Saint Díoma, teacher of St Declan of Ardmore, patron-saint of Kildimo in Co. Limerick in Ireland (5th century)^[18]
• Saint Modoald, Archbishop of Trier, related by blood and united by friendship with most of the saints of the Merovingian period (640)^[2][18]
• Saint Rictrudis, Abbess of Marchiennes Abbey in Flanders (688)^{[18][note 5]}
• Saint Æthelhard, Archbishop of Canterbury (805)^[18]

• Saint Euthemius (Euthymius), Patriarch of Jerusalem (c. 1084? c. 1224?)^[19])^{[20][note 6]}
• Saint Nikitas the Sinaite^[21]
• New Martyr John of Serres (15th century)^[7][22]
• Saint Theophanes, Bishop of Solea (Solia), Cyprus, later a hermit in the Troodos Mountains; the Outpourer of Myrrh (1550)^{[23][note 7]}
• Monk Dorotheus, (disciple of St. Dionysius of Troitse-Sergiyeva Lavra) (1622)^{[7][note 8]}
• Venerable Dionysius of Radonezh, Archimandrite of the Troitse-Sergiyeva Lavra(1633)^[7][26][27]
• New Martyr John of Wallachia, at Constantinople (1662)^{[7][28][29][note 9]}
• Saint Anthony (Medvedev) of Radonezh, Archimandrite of Troitse-Sergiyeva Lavra (1877)^[7][30]
• Repose of Saint Nectarius (Tikhonov) of Optina (1928)^{[31][note 10]}
• Holy Elders of the Sofronievo-Molchensk (Molchansk) Hermitage (glorification in 2009):^{[32][33][note 11]}

• Archimandrite Theodosy (Maslov);
• Hieromonk Serapion;
• Monk Sophronius (Batovrin);
• Novice Sergius (Tikhonov), fool-for-Christ.

New martyrs and confessors

• New Martyr Abbess Athanasia (Lepeshkina), of the Smolensk Hodigitria Convent near Moscow (1931)^[7][35]
• New Hieromartyr Peter Popov, priest of Yaroslavl-Rostov (1937)^[35][36]
• Martyr Evdokia Martishkina (1938)^[36]

• Consecration of the Cathedral of the Theotokos at Kiev (in 996)^[37]
• Glorification (1913) of Hieromartyr Patriarch Hermogenes of Moscow (1612)^[7][38][39]
• Discovery of the holy relics (1961) of Saint Irene of Lesvos the Virgin-martyr (1463)^[40]
• Second Uncovering of the relics (1992) of Righteous Simeon of Verkhoturye (1642)^[35]

• 
  Sts. Domitilla, Nereus, and Achilleus, by Peter Paul Rubens.
• 
  St. Epiphanius of Salamis.
• 
  Patriarch Germanus I of Constantinople.
• 
  Patriarch Germanus I of Constantinople and the Liddskaja icon.
• 
  St. Pancratius of Rome.

• May 12/25. Orthodox Calendar (PRAVOSLAVIE.RU).
• May 25 / May 12. HOLY TRINITY RUSSIAN ORTHODOX CHURCH (A parish of the Patriarchate of Moscow)
• May 12. OCA - The Lives of the Saints.
• Complete List of Saints. Protection of the Mother of God Church (POMOG).
• May. Self-Ruled Antiochian Orthodox Christian Archdiocese of North America.
• Dr. Alexander Roman. May. Calendar of Ukrainian Orthodox Saints (Ukrainian Orthodoxy - Українське Православ'я).
• May 12. Latin Saints of the Orthodox Patriarchate of Rome.
• May 12. The Roman Martyrology.

Greek Sources

• Great Synaxaristes: (in Greek) 12 ΜΑΪΟΥ. ΜΕΓΑΣ ΣΥΝΑΞΑΡΙΣΤΗΣ.
• (in Greek) Συναξαριστής. 12 Μαΐου. ECCLESIA.GR. (H ΕΚΚΛΗΣΙΑ ΤΗΣ ΕΛΛΑΔΟΣ).

Russian Sources

• (in Russian) 25 мая (12 мая). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia - Pravenc.ru).
• (in Russian) 12 мая (ст.ст.) 25 мая 2013 (нов. ст.). Русская Православная Церковь Отдел внешних церковных связей. (DECR).