May 21 - Eastern Orthodox Church calendar - May 23
The First Council of Constantinople (381), wall painting at the church of Stavropoleos, Bucharest, Romania.
First Ecumenical Council of Constantinople (381).
Righteous Melchizedek, King of Salem.
Abraham meets Melchisedech (Mosaic in Basilica di San Marco).
May 22 - Eastern Orthodox Church calendar - May 24
Icon of the Myrrhbearing Women (The Three Marys, including Mary of Clopas) at the Tomb of Christ (Kizhi, Russia, 18th century).
St. Michael the Confessor, Bishop of Synnada.
Tomb of Sts. Donatian and Rogatian in the Basilica of Sts. Donatian and Rogatian. The tomb is empty, as the relics were transferred to Ostia in the 12th century.
Saint Patricius (Patrice), Bishop of Bayeux.