May 25 (Eastern Orthodox liturgics)

• Third Finding of the Precious Head of Saint John the Baptist (c. 850)[1][2]

• Martyrs Pasicrates, Valentinian, Julius and others at Dorostolum (302)[3]
• Hieromartyr Therapont of Cyprus, bishop (300-305)[4][5][6]
• Hieromartyrs Maximus and Victorinus (384)[7]
• Saint Dodo, prince of Georgia, monk of Gareji (596)[5]
• Saint Olbian (Albianos), monk.[8]

• Hieromartyr Urban, Pope of Rome (230)[9][10]
• Martyr Celestine, in Rome.[11]
• Saint Dionysios (Dionysius Mariani, Denis), Bishop of Milan (359)[10][12]
• Saint Zenobius, first Bishop of Florence (390)[10][13]
• Saint Leo of Troyes, monk who succeeded St Romanus as Abbot of Mantenay near Troyes, France (c. 550)[10][14]
• Saints Injuriosus and Scholastica, a married couple in the Auvergne in France who lived in virginity and holiness (c. 550)[14]
• Saint Aldhelm, Bishop of Sherborne (709)[10][15]
• Saint Dúnchad mac Cinn Fáelad (Dunchadh), the eleventh abbot of Iona (707–717) in Scotland (717)[14]
• Hieromartyrs Gerbald, Reginhard, Winebald and Worad, of the monastery of St Bertin in France, all martyred by the Danes (862)[14]
• Saint Egilhard, eighth abbot of Cornelimünster near Aachen in Germany, martyred by Vikings at Bercheim (881)[14]
• Saint Gennadius of Astorga, Bishop of Astorga, later a hermit (936)[14]

• Saint Skiota of Georgia (c. 13th century)[16]
• Saint Dmitry, Price of Uglich, son of Andrey Vasilyevich (c. 1540)[17][note 2]
• Saint Thekla of Pereyaslavl, nun, (mother of St. Daniel, Abbot of Pereyaslavl-Zalesski +1540) (16th century)[18]
• Saint Innocent, Archbishop of Cherson and Taurica (1857)[3][19][20][note 3]
• Synaxis of the Saints of Volhynia:

• Yaropolk, Stephen, Macarius, Igor and Juliana.[3][21]

• Icon of the Mother of God "the Helper of the sinners" from Koretsk.[23]
• Commemoration of the Reunion of 3,000,000 Uniates with the Orthodox Church at Vilnius in 1831 (1831)[3][5]
• Repose of recluse George of Zadonsk (1836)[5][24]
• Finding of the holy icon of Saint Demetrios the Myrrh-gusher, in Ermoupolis on the island of Syros, in the Cyclades, Greece (1936)[25]
• Commemoration of Protopresbyter John Labunsky of Nizhyn (1945)[26][note 4]

• 
  Finding of the Precious Head of Saint John the Baptist (Menologion of Basil II)
• 
  Icon of the Third Finding of the Head of John the Forerunner (Konetz, 19th century, Russia)
• 
  A portrait of Pope Saint Urban I.
• 
  Relics of Saint Dionysius, Bishop of Milan (Cathedral of Milan).
• 
  St. Stained glass window of St. Aldhelm, installed in Malmesbury Abbey in 1928.
• 
  St. Innocent, Archbishop of Cherson and Taurica.

• May 25/June 7. Orthodox Calendar (PRAVOSLAVIE.RU).
• June 7/May 25. HOLY TRINITY RUSSIAN ORTHODOX CHURCH (A parish of the Patriarchate of Moscow).
• Complete List of Saints. Protection of the Mother of God Church (POMOG).
• May 25. OCA - The Lives of the Saints.
• Dr. Alexander Roman. May. Calendar of Ukrainian Orthodox Saints (Ukrainian Orthodoxy - Українське Православ'я).
• May 25. Latin Saints of the Orthodox Patriarchate of Rome.
• May 25. The Roman Martyrology.

Greek Sources

• Great Synaxaristes: (in Greek) 25 ΜΑΪΟΥ. ΜΕΓΑΣ ΣΥΝΑΞΑΡΙΣΤΗΣ.
• (in Greek) Συναξαριστής. 25 Μαΐου. ECCLESIA.GR. (H ΕΚΚΛΗΣΙΑ ΤΗΣ ΕΛΛΑΔΟΣ).

Russian Sources

• (in Russian) 7 июня (25 мая). Православная Энциклопедия под редакцией Патриарха Московского и всея Руси Кирилла (электронная версия). (Orthodox Encyclopedia - Pravenc.ru).
• (in Russian) 25 мая (ст.ст.) 7 июня 2013 (нов. ст.). Русская Православная Церковь Отдел внешних церковных связей. (DECR).