May 4 (Eastern Orthodox liturgics)

• Virgin-martyr Pelagia of Tarsus in Asia Minor (287)[1][2]
• Hieromartyr Albian (Olbian), Bishop of Anaea in Asia Minor, and his disciples (284-303)[3]
• Martyrs Aphrodisius, Leontius, Anthony, Valerian, Macrobius, and 60 others, monks at Scythopolis of Palestine (beginning of the 4th century)[4][5]
• Hieromartyr Silvanus of Gaza, bishop, and with him 40 martyrs (311)[2][6][7] (see also: October 14)
• Saint Hilary of the desert, the Wonderworker.[8][9]
• Saint Nicephorus of Medikion, abbot and founder of Medikion Monastery (813)[10]
• Saint Athanasios of Corinth, bishop (10th-11th century)[11]

• Hieromartyr Porphyrius (250)[2][12]
• Saint Curcodomus, a deacon in Rome sent to help St Peregrinus (2nd century)[2][12]
• Hieromartyr Erasmus of Formiae, bishop in Campania, and 20,000 martyrs with him (303)[7]
• Martyrs Florian and 40 companions, at Lorsch, Austria (304)[2][12][13]
• Saint Monica of Tagaste, the mother of St. Augustine of Hippo (387)[2][14]
• Saint Nepotianus, nephew of St Heliodorus, Bishop of Altino near Venice in Italy (395)[12][15]
• Saint Venerius of Milan, second bishop of Milan, a loyal supporter of St John Chrysostom (409)[2][12]
• Saint Conleth, first Bishop of Kildare (c. 519)[12] (see also: May 3 and May 10)[16][17][18][19]
• Saint Anthony du Rocher, a disciple of St Benedict and companion of St Maurus in his mission to France, founder of the monastery of Saint Julian in Tours (6th century)[12]
• Saint Æthelred (Ethelred, Ailred), king of Mercia and monk (716)[7][12]
• Saint Sacerdos of Limoges, Bishop of Limoges (720)[12]
• Saint Gotthard of Hildesheim, became Bishop of Hildesheim in 1022 and did much to spread the Faith (1038)[12]

• Saint Theodosia (Fedosia), princess of Vladimir, (wife of Jaroslav Vsevolodovich; mother of St. Alexander Nevsky) (1244)[20]
• Venerable Nicephorus (the Solitary, the Hesychast) of Mount Athos, teacher of St. Gregory Palamas (before 1300)[21][22]
• The Alfanov brothers of Novgorod:

• Saints: Nicetas, Cyril, Nicephorus, Clement, and Isaac of Novgorod; founders of the Sokolnitzki Monastery in 1389.[23]

• Translation of the relics of the Righteous Lazarus and Saint Mary Magdalene, Equal-to-the-Apostles, to Constantinople[5][27]
• Icon of the Mother of God "Staro Rus" (Staraya Russa) Old Russian (1570)[24][28]

• 
  St. Pelagia of Tarsus (Menologion of Basil II, 10th century).
• 
  The Martyrdom of Erasmus of Formiae.
• 
  St. Florian.
• 
  St. Monica of Tagaste, mother of St. Augustine of Hippo.
• 
  Altar with sarcophagus containing the corpses of Sts. Venerius, Marolus, Glycerius, Lazarus, bishops of Milan (San Nazaro Maggiore basilica in Milan).
• 
  Stained glass window (1890): Foundation of the church of St John's Church, Chester, England, by king Æthelred of Mercia 689.
• 
  New Hieromartyr Protopresbyter Basil Martysz of Teratyn.

• Complete List of Saints. Protection of the Mother of God Church (POMOG).
• May 4/17, Orthodox Calendar (PRAVOSLAVIE.RU)
• May 17, 2011 / May 4, HOLY TRINITY RUSSIAN ORTHODOX CHURCH (A parish of the Patriarchate of Moscow)
• May 4, 2011, OCA - The Lives of the Saints.
• May 4. Latin Saints of the Orthodox Patriarchate of Rome.
• May 4, The Roman Martyrology.

Greek Sources

• Great Synaxaristes: (in Greek) 4 ΜΑΪΟΥ, ΜΕΓΑΣ ΣΥΝΑΞΑΡΙΣΤΗΣ.
• (in Greek) Συναξαριστής. 4 Μαΐου. ECCLESIA.GR. (H ΕΚΚΛΗΣΙΑ ΤΗΣ ΕΛΛΑΔΟΣ).

Russian Sources

• (in Russian) 17 мая (4 мая). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia - Pravenc.ru).
• (in Russian) 4 мая (ст.ст.) 17 мая 2013 (нов. ст.). Русская Православная Церковь Отдел внешних церковных связей. (DECR).