Commemoration of the Founding of Constantinople (324)
Feast days
2026
Old calendar
Not kept on this calendar this year.
New calendar
- , commemoration
2027
Old calendar
Not kept on this calendar this year.
New calendar
- , commemoration
Also commemorated on 11 May 2026
- ✚Holy Equal-to-the-Apostles Methodius († 885) and Cyrill († 869), teachers of the Slavs
- Hieromartyr Mocius the Presbyter of Amphipolis in Macedonia († c.295)
- Holy Equal-to-the-Apostles Rostislav, prince of Greater Moravia († 870)
- New Hieromartyr Priest Michael († 1920)
- New Hieromartyr Alexander, Archbishop of Khar′kov († 1940)
- Venerable Sophronius, Recluse of the Kiev Caves († 13th century)
- Hieromartyr Joseph, First Metropolitan of Astrakhan († 1672)
- Saint Nicodemus, Archbishop of Serbia († 1325)
- New Martyrs Dioscorus and Argirus (1808)
- Icon of the Mother of God of Constantinople