May 11 (Eastern Orthodox liturgics)

• Martyr Evellius, under Nero (66)[1][2]
• Martyrs Maximus, Bassus, and Fabius (284–305)[2][3]
• Hieromartyr Mocius (Mucius), presbyter of Amphipolis in Macedonia, beheaded in Byzantium (288)[4][note 2]
• Martyr Armodius[5][note 3]
• Martyr Acacius of Lower Moesia[6]
• Saints Cyril and Methodius, Equal-to-the-Apostles and Enlighteners of the Slavs (869, 885)[7][8] (see also: July 17 )
• Saints Clement of Ohrid (916), Sabbas (10th century), Angelarius (Angelyar) (ca. 886), Gorazd (896), and Naum of Preslav (910) — Disciples of Saints Cyril and Methodius and missionaries of the Slavs, Wonderworkers and Equal-to-the-Apostles[9][note 4]
• Saint Rostislav the Prince of Great Moravia, Confessor of the Faith (870)[6][8] (see also: October 29)

• Hieromartyr Anthimus of Rome, and martyrs Sisinius the deacon with Diocletius and Florentius (disciples of St. Anthimus), (284–305)[2][11][12]
• Saint Principia of Rome, a holy virgin in Rome and disciple of St Marcella (420)[12]
• Saint Mammertus, Archbishop of Vienne (475)[12][13]
• Saint Possessor of Verdun, Bishop of Verdun, he and his flock were greatly troubled by the barbarian invasions of Franks, Vandals and Goths (c. 486)[12]
• Saint Tudy (Tudinus, Tegwin, Thetgo), a disciple of St Brioc in Brittany (5th century)[12]
• Saint Credan of Cornwall, hogherd.[14]
• Saint Gangulphus (760)[12]
• Saint Fremund of Dunstable, Anglo-Saxon hermit, killed by his kinsman Oswy with the help of Danish invaders who had also murdered King Edmund (866)[12]
• Saint Odo of Cluny, the second Abbot of Cluny (942)[12]
• Saint Mayeul (Majolus, Maieul), Abbot of Cluny (994)[6][12]
• Saint Odilo of Cluny (1049)[12]

• Martyrs Olympia, abbess of Mytilene, and nun Euphrosyne (1235)[6][15]
• Saint Sophronius of the Kiev Caves, recluse (13th century)[6][16][17][note 5]
• Saint Nicodemus of Pec, Archbishop of Serbia (1324)[6][18]
• Hieromartyr Joseph, first Metropolitan of Astrakhan (1672)[6][19][20]
• Blessed Christopher of Georgia (Christesias), monk at the Monastery of St. John the Baptist, at the David Gareja monastery complex, "The Thebaid of Georgia" (1771/1871)[21][22][note 6]
• New Martyr Dioscorus (Dioscorides) the New, of Smyrna[6][23][24]
• New Martyr Argyrus (Argyrus, Argyres) of Thessalonica (1806/1808)[6][24][25]
• Saint Theophylact, bishop of Stavropol and Ekaterinodar (1872)[26]

• Commemoration of the Founding of Constantinople (330) as Capital of the Roman Empire[29][30]
• Consecration of the Saint Sophia Cathedral in Kiev (960).[31]

• 
  Saints Saints Cyril and Methodius, Equals-to-the-Apostles.
• 
  St. Clement of Ohrid.
• 
  Saint Naum of Preslav.
• 
  St. Rostislav the Prince of Great Moravia, Confessor of the Faith.
• 
  St. Mamertus, Archbishop of Vienne.
• 
  Sancreed church and war memorial, Cornwall.
• 
  St. Gangulphus of Burgundy.
• 
  St. Odo of Cluny.
• 
  St. Odo of Cluny.
• 
  St. Majolus of Cluny.
• 
  Saint Sophia Cathedral in Kiev.

• May 11/24. Orthodox Calendar (PRAVOSLAVIE.RU).
• May 24 / May 11. HOLY TRINITY RUSSIAN ORTHODOX CHURCH (A parish of the Patriarchate of Moscow).
• The Lives of the Saints – May 11 OCA
• May. Self-Ruled Antiochian Orthodox Christian Archdiocese of North America.
• May 11. Latin Saints of the Orthodox Patriarchate of Rome.
• May 11. The Roman Martyrology.

Greek Sources

• Great Synaxaristes: (in Greek) 11 ΜΑΪΟΥ. ΜΕΓΑΣ ΣΥΝΑΞΑΡΙΣΤΗΣ
• (in Greek) Συναξαριστής. 11 Μαΐου. ECCLESIA.GR. (H ΕΚΚΛΗΣΙΑ ΤΗΣ ΕΛΛΑΔΟΣ).

Russian sources

• (in Russian) 24 мая (11 мая). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia – Pravenc.ru).
• (in Russian) 11 мая (ст.ст.) 24 мая 2013 (нов. ст.). Русская Православная Церковь Отдел внешних церковных связей. (DECR).