thumb|An [[Eastern Orthodox Church|Eastern Orthodox cross]]
May 21 - Eastern Orthodox Church calendar - May 23
All fixed commemorations below celebrated on June 4 by Orthodox Churches on the Old Calendar.
For May 22nd, Orthodox Churches on the Old Calendar commemorate the Saints listed on May 9.
Feasts
- Commemoration of the Holy Fathers of the Second Ecumenical Council (381)
Saints
- Righteous Melchizedek, King of Salem (ancient Jerusalem) (c. 2000 BC)
- Martyr Sophia the Healer, a physician, by beheading.
- Martyr Marcellus, by being placed in molten lead.
- Martyr Codratus (Quadratus), by being dragged by horses. <small>(see also: March 10)</small>
- Martyr Basiliscus of Comana (c. 308) <small>(see also: March 3)</small>
- Hieromartyrs Donatus, Bishop of Thmuis, the priest Macarius, and the deacon Theodore (c. 316)
Pre-Schism Western saints
- Saint Ausonius, first Bishop of Angoulême (1st or 3rd century)
- Saint Marcian of Ravenna, Bishop and Confessor (c. 127)
- Martyrs Castus and Emilius, by fire, in Carthage (250)
- Martyrs Timothy, Faustinus and Venustus, in Rome, under Julian the Apostate (362)
- Saint Helen of Caernarfon (Elen Luyddog, lit. "Helen of the Hosts"), daughter of a Romano-British ruler, wife of Emperor Magnus Maximus, and a founder of churches in Wales (late 4th-century)
- Saint Helen of Auxerre (c. 418)
- Saint Julia of Corsica the martyr, who was crucified (440)
- Saint Quiteria the virgin-martyr, in Spain (5th century)
- Saint Romanus of Subiaco (Romanus of Auxerre), ascetic who ministered to Saint Benedict of Nursia (560)
- Saint Fulk (c. 600)
- Saint Conall (Conald, Coel), of Inniskeel (Inniscoel, Innis-coel), County Donegal, Abbot of the island monastery of Inniskeel (7th century)
- Saint John of Parma, abbot of Saint John's at Parma from 973 to c. 982, then under Cluniac observance (c. 982)
- New Hieromartyr Zachariah, priest of Prussa (1802)
- Blessed James, youth, of Borovichi, Novgorod, Wonderworker (1540)
- New Martyr Demetrios of Peloponnesos (1803) <small>(see also: April 14)</small>
- Venerable Monk-martyr Paul of Mt. Athos, at Tripolis, Peloponnesus (1818)
New martyrs and confessors
- Saint Innocent (Yastrebov), Archbishop of Astrakhan, Confessor (1928)
- New Hieromartyr Maxim (Zhizhilenko), Bishop of Serpukhov (1931)
- New Hieromartyr Michael Borisov, Archpriest, of Uglich (1942)
Other commemorations
- Synaxis of the Cyprus Icon ("Sophianois" Icon) of the Most Holy Mother of God.
- "Surety of Sinners" Icon of the Most Holy Theotokos, Korets (1622)
- Repose of Eldress Macrina of Volos (Macrina of Portaria) (1995)
